Chapter 7: Doom of Ythryn

Ythryn is haunted by nothics who were once powerful netherese spellcasters.

Ythryn rests in the silent depths of the Reghed Glacier. Ice encloses the enclave on all sides, yet the magic imbued in its stonework shields it from utter destruction. Ythryn is now a corpse city—a tomb for those who perished here and a death trap for those who dare to explore its ruined, glaciated halls.

Running This Chapter

Before running your first game session in the necropolis, review the “Iriolarthas the Demilich” and “The Fall of Ythryn” sections below, as well as the “Dealing with the Arcane Brotherhood” and “Auril’s Wrath” sections at the end of the chapter.

Character Advancement

Ideally, the characters are 9th level when they first arrive at Ythryn. You decide how quickly they advance in level. Treat the following as suggestions:

• The characters gain a level after overcoming the challenges of all eight towers of magic (areasarea Y4, area Y7, area Y11, area Y18, area Y20, area Y22, area Y24, and area Y26).
• The characters gain a level when they reach Iriolarthas’s study (area area Y19q).
• The characters gain a level if they accomplish something extraordinary, such as destroying Iriolarthas the demilich, all three of Auril’s forms, or the obelisk in area area Y21.

If you follow the suggestions above, the characters could be as high as 12th level by the adventure’s conclusion—an important consideration if you intend to continue the campaign beyond this adventure.

Iriolarthas the Demilich

Iriolarthas, once a powerful lich and before that a human wizard of Netheril, exists today as a demilich that haunts the ruins of Ythryn. Iriolarthas endures as a deteriorating skull that drifts about the necropolis in lonely despair. Wispy symbols of the eight schools of magic form above it and quickly dissipate.

A demilich is what becomes of a lich that neglects to feed souls into its phylactery, and Iriolarthas’s phylactery has been empty for nearly two thousand years, buried under the rubble of Ythryn far from the demilich’s reach. Having lost its body and its spellcasting abilities, the demilich holds out hope that other Netherese wizards will come to its rescue, unaware that the Empire of Netheril no longer exists. Though it has been trapped in Ythryn under the ice for centuries, the demilich has a very poor sense of how much time has passed.

When confronted by new arrivals, the demilich assumes they are rescuers from another Netherese enclave and watches to see what they do. The demilich has no means of communication and can’t be contacted telepathically, so it judges new arrivals in silence. Characters who observe Iriolarthas and succeed on a DC 13 Wisdom (Insight) check can ascertain that the demilich is watching them closely to see how they react to their surroundings. If the demilich concludes, based on its observations, that the characters are not a rescue team from another Netherese enclave, it tries to destroy them before they can steal any of Ythryn’s secrets. The same is true of invasive NPCs such as members of the Arcane Brotherhood. A party can fool the demilich into thinking they belong in Ythryn by succeeding on a DC 13 Charisma (Deception) group check. If the group check is successful, Iriolarthas believes the party is what it pretends to be; on a failed group check, the demilich sees through the party’s deception and becomes hostile toward the characters. If the demilich thinks that the characters are rescuers, given how they appear and act, it follows them around until something happens to change its mind.

Although it lacks the means to communicate, the demilich dimly recalls the circumstances that led to its present situation.

The Fall of Ythryn

After using the Ythryn mythallar) to lift the enclave of Ythryn into the sky, Iriolarthas and his apprentices traveled to the frozen north in search of relics of Ostoria, a bygone empire of magic-wielding giants that waged war against the dragons forty thousand years earlier. After many fruitless excavations, they found a large stone spindle bearing strange sigils at the bottom of the Sea of Moving Ice and brought it back to Ythryn for study in the fall of −343 DR, the Year of Chilled Marrow. During one of their experiments, something went wrong—a flash of power from the spindle caused the Ythryn mythallar to shut down, which in turn caused the city to fall out of the sky and crash into the ice below.

The inhabitants of Ythryn had only a few moments to react as the city fell. Iriolarthas conjured a doorway to a magical demiplane and stepped through it just in time. As Ythryn settled into its icy grave, all magic in the city became undone for a brief time, as though something was trying to siphon it all away. The demiplane expelled Iriolarthas in that instant, trapping the lich in Ythryn, and became a living demiplane (see appendix C). Iriolarthas searched the ruins of the city for his spellbook and his phylactery, recovering only the former. He also found several magical servants in stasis that had survived the devastation, as well as a handful of apprentices who had used their spells in ingenious ways to escape death.

Some of those inside tried to flee Ythryn, but glacial ice blocked all conventional routes of escape, and attempts to leave by magic were thwarted by a troublesome intercessor: the mysterious spindle in Iriolarthas’s citadel was still putting out magical pulses of energy to hinder spellcasting. By the time this disruption stopped some fifty years later, fear and madness had warped the minds of the apprentice mages, transforming them into nothics. Meanwhile, Iriolarthas grew increasingly feeble until, finally, the lich’s skeletal body turned to dust.

Fate of Netheril

The Empire of Netheril arose more than five thousand years ago. Those who follow the Dalereckoning calendar would place the date of Netheril’s birth at −3859 DR.

The Netherese legacy began with the discovery of the Nether Scrolls. These long, golden scrolls taught Netherese arcanists how to wield magic beyond their wildest fantasies. It took centuries, but the Netherese who mastered the power of the Nether Scrolls became a ruling class, living on great flying cities or taking refuge in remote, subterranean lairs.

Despite their great power, the Netherese faced a growing threat. Under the heart of their empire lived spellcasting aberrations called phaerimm. Using their ability to drain magic, the phaerimm began to unravel the Weave, without which Netheril would collapse into ruin. In −339 DR, four years after the fall of Ythryn, the empire’s most powerful arcanist, Karsus, attempted to neutralize the phaerimm threat by casting a spell of unparalleled power that would enable him to replace Mystryl as the god of magic, giving him absolute control over the Weave. Mystryl countered Karsus at a key moment during the casting of the spell, a feat she could accomplish only by sacrificing herself and tearing the Weave. Karsus was slain instantly, and for a time thereafter, most of the creatures of the world were either without magic or simply unable to control it.

Without great magic to keep them aloft, the remaining flying cities of Netheril crashed to the ground, and many arcanists who survived were driven mad. Once magic came back into use, Netherese arcanists could no longer cast their mightiest spells as they had before, forcing them to resort to traditional wizardry. Four hundred years after Karsus cast his spell, the Netherese empire was no more—crushed by its enemies and undone by its own hubris.

In the Forgotten Realms, Netheril is the definitive lost empire. It rose to unparalleled heights but eventually fell into ruin. If you’ve ever played a science fiction game that includes the concept of a lost, highly advanced civilization, then you can begin to imagine what ancient Netheril must have been like. Out of this empire came many of the fearsome monsters, bizarre dungeons, and wondrous magic items found in Faerûn today.

Necropolis of Ythryn

When the characters arrive at Ythryn, read:

The tunnel opens into a vast grotto enclosed by gleaming ice. Consigned to this frozen sepulcher is a fantastic city sculpted by ancient magic and illuminated in a haunting way by green and purple lights that shed no warmth. The city is slightly tilted, its spires leaning away from you as though recoiling from your presence.

You stand atop a causeway of frost-covered ice that stretches toward the city like the dead, frozen tongue of some hideous behemoth out of whose mouth you’ve just stepped.

Show your players map 7.1. Permission is granted to photocopy this player-friendly map of the necropolis for home game use. Map 7.2 is the DM’s version of the same map. Because the city is magically lit, the characters can see almost all of it from their vantage point on the ice bridge.

Most of the city’s buildings are swathed in ice and ruined by time. Many of its districts were pulverized when Ythryn plunged from the sky, and the rest have fallen into disrepair in the centuries since. Use the information below to add life to this accursed city of the dead.

Denizens of the Necropolis

Ythryn is home to many threats. Its most important denizens are summarized below:

• The demilich Iriolarthas dwells in the central spire (area area Y19) but can be encountered anywhere in the necropolis.
• Mages who survived Ythryn’s fall but succumbed to the arcane blight (see “area Magical Effects” below) became nothics that speak Loross instead of Undercommon (see the “area Loross: The Netherese Tongue” sidebar).
• Immortal servants known as magen (see area appendix C) tirelessly perform their duties or wait in silence for new orders.
• Deadly living spells (see appendix C) guard a handful of locations in the city.

Random Encounters

After each hour the characters spend exploring the city, or each time the characters conduct a thorough search of an unnumbered building on the map, roll percentile dice and consult the Ythryn Encounters table to determine if the party has a random encounter. Some random encounters have variants if Avarice or Auril is present in the necropolis (see “area Dealing with the Arcane Brotherhood” and “area Auril’s Wrath” at the end of the chapter).

Ythryn Encounters

Magical Effects

The following magical effects are present throughout the necropolis:

• Continual flame spells illuminate street lamps as well as building interiors and exteriors.
• A powerful enchantment stabilizes gravity so that creatures stand upright even though the city rests at an angle. This enchantment extends over the enclave in a hemisphere whose ceiling is 800 feet high.
• Humanoids who remain in the necropolis for too long are likely to contract an arcane blight (see below).

Arcane Blight

Any humanoid that spends 12 hours in the necropolis must succeed on a DC 15 Constitution saving throw or contract an arcane blight. This magical disease transforms the humanoid into a nothic, but only after the victim experiences hallucinations and feelings of isolation and paranoia. Other symptoms include clammy skin, hair loss, and myopia (nearsightedness).

A player character infected with the arcane blight gains the following flaw: “I don’t trust anyone.” This flaw, which supersedes any conflicting flaw, is fed by delusions that are difficult for the character to distinguish from reality. Common delusions include the belief that that allies are conspiring to steal the victim’s riches or otherwise turn against the victim.

Whenever it finishes a long rest, an infected humanoid must repeat the saving throw. On a successful save, the DC for future saves against the arcane blight drops by 1d6. If the saving throw DC drops to 0, the creature overcomes the arcane blight and becomes immune to the effect of further exposure. A creature that fails three of these saving throws transforms into a nothic under the DM’s control. Only a wish spell or divine intervention can undo this transformation.

A greater restoration spell or similar magic ends the infection on the target, removing the flaw and all other symptoms, but this magic doesn’t protect the target against further exposure.

Rite of the Arcane Octad

To pass through the force field that surrounds the Spire of Iriolarthas (area area Y19) and the Ythryn mythallar (area area Y23), one must perform the Rite of the Arcane Octad on the spire’s doorstep (area area Y6). To learn this ritual, the party must explore eight locations in the city and translate the inscriptions found therein. Once the inscriptions are translated and assembled in order, the eight steps of the ritual become clear:

• Step 1 Hold a wand crafted from the Nether Oak over your heart.
• Step 2 Summon a flame in your palm.

Step 3

Speak a secret about yourself aloud. (The secrets in appendix B might come into play here and in step 4.)

• Step 4 Compel another to share a secret with you.
• Step 5 Quench the flame in ice.
• Step 6 Mask your appearance.
• Step 7 Draw a circle on the ground using the ashes of a corpse.
• Step 8 Stand inside the circle and consume poison.

This ritual was designed to test visitors' magical aptitude but can be performed without casting spells. For example, an adventurer could light a handful of lamp oil to “summon a flame” (taking 1 fire damage in the process). Any creature that performs all eight steps of the ritual in the correct order outside the spire can pass through the force field thereafter.

Exploring the Ruins

As the characters explore the necropolis, call the players' attention to any numbered locations their characters can see; these are typically the most intact buildings. Unless the players say otherwise, assume that the characters explore at a cautious rate of 200 feet every 5 minutes.

Searching an unnumbered location takes 30 minutes and requires a check for random encounters. Roll once on the Ythryn Treasures table to determine if the characters find anything of value in the location.

Ythryn Treasures

Ythryn Lore

As the characters explore Ythryn, they piece together a picture of what life was like in the enclave. Whenever a location instructs you to reveal some of Ythryn’s lore, roll a d20 and refer to the Ythryn Lore table. If you get a result that’s come up before, roll again or choose a different result.

Ythryn Lore

Necropolis of Ythryn Locations

Necropolis Locations (Y1-Y9)

The following locations are keyed to map 7.2, which is the DM’s version of the necropolis map.

Y1. Ice Causeway

Characters can use this naturally formed causeway of solid ice to enter the city. As the characters approach the end of the causeway, read:

Green and purple lights cast an otherworldly glow upon the frost draping the silent city. Clawing spires, broken domes, and steeples leaning at odd angles surround a huge citadel.

At the foot of the causeway, a giant statue lies prone and motionless, its surfaces gleaming with rime.

The city’s dominating feature is the Spire of Iriolarthas (area area Y19), which is sealed inside a magical force field.

Dead Tomb Tapper

The statue at the end of the causeway is a 21-foot-tall tomb tapper (see appendix C) that was killed by drow invaders less than a tenday ago. The tomb tapper chased the drow to this point before they finally killed it. (The characters might have encountered the drow already in chapter 6.) The tomb tapper looks like a faceless, misshapen giant. It turned to stone when it died, leaving behind its big sledgehammer.

Y2. Wizard Spires

Several crooked spires branch off the enclave’s perimeter wall, with bridges leading to their entrances. If a character approaches one of these outer towers, read:

A stone walkway leads to a tower that claws upward and inward, its pointed roof leaning menacingly overhead. Narrow windows pierce its walls, gargoyles cling to its eaves, and a doorway at the tower’s base gapes open.

Two of the outer spires have broken off. One crashed in Icewind Dale (see area chapter 2), and the other is buried elsewhere in the glacier (see chapter 6). The remaining twelve spires are intact, though two are almost buried in ice. There is a 20 percent chance per tower that 1d3 + 1 Gargoyle cling to the outside of it. (The other gargoyles clinging to the tower are inanimate statues.) Living gargoyles swoop down to attack anyone who crosses the gantry approaching the tower.

These towers were once occupied by mages and contained laboratories, libraries, and living quarters. Now they lie in ruins. Map 2.10 gives you an idea of how the interior of each spire is laid out.

Y3. Chain Lightning Stadium

The air around this amphitheater is charged with static. Cracked steps descend to the stadium floor, where a tiny glittering object rests on a pedestal of black stone. Three metal masts rise from the arena like gigantic tridents, each one emitting a low hum. The branches of each trident are twenty-five feet off the ground and extend fifty feet into the air.

A sport called Chain Lightning was played in this stadium. This event, which pitted mortals against each other in an electrified arena, enjoyed great popularity. An ornate trophy cup sits on a pedestal at one end of the arena floor, held in place by magic.

At ground level, the oval arena is 120 feet long and 50 feet across at its widest point. The three masts are 100 feet tall, spaced 40 feet apart, and emit electrical fields.

Triggering the Game

The first time a creature steps onto the playing field, a dome of crackling electricity encloses the entire stadium. Nothing can physically pass through this barrier, which is immune to all damage and can’t be dispelled by dispel magic. The barrier also extends into the Ethereal Plane, blocking ethereal travel. Any creature that touches the barrier for the first time on a turn takes 40 (9d8) lightning damage. When the barrier appears, read:

The shimmering head and shoulders of a woman blink into existence above the arena floor. Electrical currents course over her metal teeth, and her form stutters and flickers as she speaks in a strange language.

The illusory visage speaks in Loross, the dead language of Netheril (see the “area Loross: The Netherese Tongue” sidebar). It says, “So, a new challenger enters the arena! You have thirty seconds to choose your teammates for a game of Chain Lightning!”

The illusory figure disappears after making its announcement, and adventurers on the playing field have thirty seconds to round out their team of six. Any spaces left over on the team are filled by obedient galvan magen (see area appendix C) in black garments. The rival team is composed of six galvan magen in white garments. All these magen are magically summoned to the field.

The rules of Chain Lightning are summarized in the accompanying sidebar. If the characters aren’t familiar with the rules, they have disadvantage on all skill checks made to play the game. (A written copy of the game’s rules can be found in area area Y9.) When the game ends, the electrical barrier enclosing the stadium vanishes, and the trophy levitates from its pedestal and drifts over to the member of the winning team nearest to it. The game can’t be played again until a new trophy of similar value is placed upon the pedestal.

If an all-magen team wins the game, the winners collect their prize and disappear, taking the trophy with them.

Treasure

The trophy can’t be removed from its pedestal until it is won. If a creature tries to move the trophy before then, the pedestal discharges a bolt of lightning that deals 18 (4d8) lightning damage to the creature. The trophy cup is made from mithral embedded with three blue spinel gemstones and is worth 1,800 gp. While carried by a member of the winning team, it functions as a stone of good luck.

Chain Lightning

Chain Lightning is a game in which two teams of six players compete against each other. To win, a team must eliminate the other team’s players by hitting them with a 3-inch-diameter iron ball. A player struck by the thrown ball is eliminated and teleported to the sidelines. The game ends when all of one team’s players have been eliminated.

When the game begins, an iron ball magically appears in a random location on the arena floor roughly equidistant from the two teams. The ball is a simple ranged weapon with the finesse and thrown properties. Its range is 120 feet, and it deals 1d4 bludgeoning damage on a hit.

To simulate a game of Chain Lightning, follow these steps:

Step 1: Every player makes a Dexterity (Athletics) check. The individual with the highest roll gets the ball, and that person’s team is on offense. Resolve a tie with a Strength (Athletics) contest.

Step 2: To simulate the ball being passed around, every player makes a DC 15 Dexterity (Athletics) check. If the team on offense gets more successes than the team on defense, one player on offense can try either to hurl the ball between the metal tines of an electrified mast, hoping to impart an electrical charge to the ball, or make a ranged weapon attack with the ball against a player on defense. Each option is described below:

,- Hurling the ball between the tines of an electrified mast requires a successful ranged attack roll against AC 15. If this attack hits, the ball becomes electrically charged as it passes between the tines. Repeat step 1 to determine which team gets custody of the electrically charged ball.,- If the ball is thrown at a player on defense and it hits, the player struck by the ball is eliminated. If the ball is electrically charged when it hits, it deals an additional 3 (1d6) lightning damage to the eliminated player, and an arc of lightning shoots from the ball and automatically hits another randomly determined player on the same team. This second player takes 3 (1d6) lightning damage and is also eliminated. If the ball is thrown at a player and it misses, it loses its electrical charge if it has one. Repeat step 1 to determine which team gets custody of the ball.

How to Win: Repeat step 2 until one team has eliminated all the players on the other team.

Y4. Tower of Abjuration

This tower reaches upward like a talon, its stonework studded in chiseled runes. A blue light shines from its highest window.

A detect magic spell cast here reveals an aura of abjuration magic. Runes cover every inch of this tower’s exterior. A glyph for the symbol (insanity) spell is hidden among them. A character who searches the outside of the tower for traps finds and identifies the glyph with a successful DC 18 Intelligence (Arcana) check. The glyph triggers when a creature steps through the tower’s entrance and resets after 24 hours.

Once inside, the characters can ascend to the top of the tower. When they arrive there, read:

A huge anvil chiseled with vivid blue runes rests in the center of a thirty-foot-diameter, thirty-foot high circular chamber. Resting atop it is a hammer adorned with matching runes.

Six armored figures stand guard around the anvil. At the rear of the chamber, the frozen corpse of a wizard lies in a pile of rubble. Blue flames flicker from braziers spaced around the room, illuminating a carved inscription on the ceiling.

Six demos magen (see area appendix C) guard the anvil, which has the power to destroy other magic items. The anvil was a source of vexation for Ythryn’s tomb tappers, which believe magic items to be sacred. When Ythryn collapsed, the protective wards surrounding the tower unraveled, and one of the tomb tappers seized the opportunity to kill the anvil’s creator, High Abjurer Taruth. The wizard’s mauled body lies in this chamber, the stony floor next to him broken where the tomb tapper forced its way into the room. The magen won’t let anyone use the anvil and fight to defend it.

Anvil of Disjunction

The anvil has the power to destroy any magic item that isn’t an artifact. When a character holds the anvil’s hammer for the first time, a voice inside their head, seeming to come from the anvil, says, “Bring me your items of power, and together we shall destroy them.” To destroy an item, the character must place it on the anvil and strike it three times with the hammer. Each hammer strike takes one action. On the third strike, the item disintegrates in a flash of blue light. Every time a character uses the anvil, there is a 25 percent chance that a tomb tapper (see appendix C) burrows its way into the tower to attack them (this happens only once). The anvil is anchored here and cannot be moved by any means. Removing the hammer from the tower causes it to teleport atop the anvil.

Inscription

The inscription on the ceiling is in Draconic and reads “First, shield thy heart with a wand from the Nether Oak.” This is a passage from the Rite of the Arcane Octad (see “area Rite of the Arcane Octad").

Y5. Prison

A portcullis sits askew in the 40-foot-wide, 30-foot-tall archway that serves as the only entrance to this square building. Characters who pass beneath the portcullis find themselves in a mostly abandoned prison:

A maze of cell-lined corridors fills this area.

All the cell doors, which have arcane lock spells cast on them, are made of iron, with small, barred windows set into them at eye level. Many of the cells contain the frozen bodies of prisoners who died when Ythryn crashed or who perished from starvation not long afterward.

Infirmary

If the characters spend at least 30 minutes searching the prison, they stumble upon an infirmary:

Peering through the gap in a collapsed wall, you see a fifteen-foot-square infirmary in disarray, with an operating table in the middle of the room. Leather straps extend from one side of the table, into the air above its surface, and fasten to the other side. The shape suggests that something or someone invisible is lashed to the table.

Strapped to the table is a doppelganger named Xerophon. It has been rendered invisible and placed in a state of suspended animation by a sequester spell. The spell can be dispelled (DC 17), which renders Xerophon visible and awake. The doppelganger looks like a thin, middle-aged man with a sallow complexion, one blue eye and one green eye, and a streak of silver in his long, jet-black hair. The awake doppelganger can use its action to try to slip free of the table’s leather straps, doing so with a successful DC 20 Dexterity check, or a character can use an action to loosen the straps enough for Xerophon to get free.

Shortly before the fall of Ythryn, Xerophon murdered a Netherese sage in the city, stole his identity, and tried to infiltrate the Spire of Iriolarthas. The doppelganger was caught and imprisoned. The prison warden, a Netherese wizard, was interested in studying the doppelganger and perhaps developing a potion that emulated its shapeshifting ability. The wizard made Xerophon acquiesce to a series of experiments, and in between cast sequester spells on the doppelganger as a precaution to keep it from escaping.

If questioned, Xerophon speaks Loross but switches to Common if no one in the party understands the dead Netherese tongue. The doppelganger plays the part of a low-born Netherese manservant who was sent to the prison by his master, Iriolarthas, for disobedience. Without going into much detail, Xerophon alludes to horrible magical experiments performed on prisoners by the wizard who ran the prison, saying, “I was afraid I might be next.”

Once it realizes the fate that has befallen Ythryn, Xerophon offers to help the characters search the rest of the city, allowing the doppelganger time to use its Read Thoughts ability to glean all the information it can from the characters' minds. After all, it has a lot of catching up to do. The doppelganger has no ill intentions toward the characters but places self-preservation above all else.

If the characters befriend Xerophon, they learn three facts from the area Ythryn Lore table, which Xerophon shares to build trust. The doppelganger also knows that to bypass the force field around the Spire of Iriolarthas, one must perform the eight steps of the Rite of the Arcane Octad outside the spire. The steps of the ritual are hidden inside towers dedicated to the eight arcane schools of magic. Xerophon knows the layout of the city and can lead the party to each of these towers (areas area Y4, area Y7, area Y11, area Y18, area Y20, area Y22, area Y24, and area Y26).

Y6. Spire Entrance

An arching strut of dark stone rises from this ruined district to a junction high up on the central spire. A gate engraved with arcane sigils is set into the base of the strut.

The Spire of Iriolarthas (area area Y19) is surrounded by a force field that also encompasses this area. Creatures can’t pass through the field, nor can they teleport to a location inside it. To pass through the force field, one must perform the Rite of the Arcane Octad (see “area Rite of the Arcane Octad") in front of the gate.

Any character who succeeds on a DC 10 Intelligence (Arcana) check recognizes the sigils on the gate as ancient symbols representing the eight schools of magic.

Magic Elevator

Characters who can pass through the force field can open the gate and enter the strut, which is hollow and encloses a steep passage. Any creature that enters this elevator is magically levitated to the spire entrance (area area 19a).

Y7. Tower of Conjuration

This tower is engraved with interlocking circles of stone. Yellow light spills from its topmost window, and the faint sound of brooms brushing on stonework drifts through its broken doors.

A detect magic spell cast here reveals an aura of conjuration magic. The tower’s interior is ruined but surprisingly clean, thanks to permanent unseen servant spells that continuously sweep the floors. If the characters ascend to the topmost chamber of the tower, read:

Glowing orbs are set into the walls of this thirty-foot-diameter circular chamber. Four giant hands made of shimmering force hover in the center of the room, guarding a tiny ornamental tower perched on a pedestal.

The hovering hands are four Living Bigby’s Hand (see appendix C) that attack any other creature that enters the room.

Hidden Tower

Touching the miniature tower while it is inside this chamber conjures a glowing doorway to a demiplane. The doorway is 8 feet tall, 4 feet wide, and 5 feet away from the pedestal.

If a character steps through the doorway, the fabric of reality warps and bends around them as they arrive in the demiplane: a cluttered den 40 feet long and 20 feet wide. Occupying this extradimensional den are three Night Hag named Auntie Pinch, Auntie Pillage, and Auntie Plunder. This coven frequently leaves its den to roam the Ethereal Plane in search of treasure chests tucked away using the Leomund’s secret chest spell; however, all three hags are home when the characters arrive.

In addition to their innate spellcasting abilities, the hags have the Shared Spellcasting ability of a coven (see the “Hag Covens” sidebar in the Monster Manual). The hags are prepared to let the characters leave alive in return for a simple price: a single memory plucked from each character’s mind. The hags flee their lair in ethereal form if attacked, vowing to return and seek vengeance in the adventurers' dreams.

Inscription

An inscription in Draconic is written on the wall of the hags' den. It reads “Second, summon a flame in the palm of your hand.” This is a passage from the area Rite of the Arcane Octad.

Treasure

The night hags keep their heartstones and soul bags on their persons (see the “Night Hag Items” sidebar in the Monster Manual).

Characters who ransack the hag’s den find a platinum needle (1 gp) stuck in a pincushion, a pink quartz figurine of a rabbit (50 gp), a silver necklace from which hangs a crow’s-foot pendant grasping a peridot (500 gp), a potion of invisibility in a stoppered vial made from a witch’s fingerbone, and a potion of longevity in a hollow gourd that bears a child’s face locked in a scream.

Y8. House of the Arcane

Eight tusk-like towers are embedded in the walls of this monumental building, their spires arching over its shattered roof.

This grand academy was a place of study for novice mages, where each one learned which schools of magic would become their life’s work. The place is easily entered through any of the gaping holes in its outer walls. Nothing can be salvaged from the study halls and the towers, but the auditorium holds something of interest:

Eight stained glass windows overlook a ruined auditorium. Benches glistening with frost are arrayed in broken rows, facing a raised lectern. A bejeweled goblet rests on the lectern. Steam rises from the goblet’s contents and dissipates in the cold air.

Each window in the auditorium depicts a wizard casting a spell from one of the eight schools of magic. The spells depicted are blade ward (abjuration), mage hand (conjuration), true strike (divination), friends (enchantment), dancing lights (evocation), minor illusion (illusion), chill touch (necromancy), and prestidigitation (transmutation), all of which a character can determine with a single successful DC 10 Intelligence (Arcana) check.

Magic Goblet

The goblet is embedded with eight colored crystals that represent the eight schools of magic. The liquid inside it looks and tastes like hot water. A detect magic spell reveals an aura of divination magic on the goblet and indicates that the liquid carries auras of all eight schools of magic. The liquid isn’t poisonous or harmful, and it never runs dry as long as the goblet remains in the auditorium.

A humanoid that drinks from the goblet gains a supernatural charm (see “Supernatural Gifts” in the Dungeon Master’s Guide). Roll a d8 and consult the Magic Goblet Charms table to determine which charm is bestowed. Each charm grants its recipient the power to cast a particular spell, for which Intelligence is the spellcasting ability. The recipient becomes aware of this power as soon as the charm is bestowed. Each charm also has a secret magical effect that triggers when the charm’s benefit expires; do not reveal this secret to a player before the effect occurs.

Once a creature has gained a charm from the goblet, it cannot gain another one by drinking from the goblet again.

Magic Goblet Charms

Y9. Library

This colossal building has many lofty turrets in a state of disrepair, the ground below littered with their rubble. A giant-sized door at the base of the structure stands slightly ajar.

Shelves line the walls of this labyrinthine library, which is crammed with books on every conceivable subject.

Arcanaloth Book Hunter

Soon after the adventurers enter, a bespectacled, jackal-headed humanoid paces into view carrying a bundle of scrolls. An eyeless, white, 5-foot-tall penguin in a leather harness shuffles behind it, dragging a small cart laden with books. The jackal-headed figure lets out a joyful gasp when it sees the characters and says, “Ah, you must be the librarians! Scrivenscry has need of your assistance.” The penguin shifts uneasily as its master speaks.

Scrivenscry is an arcanaloth who always refers to itself in the third person. It has a fondness for black licorice, strips of which it keeps in the pockets of its robe. The fiend is attended by Kingsport, a blind, albino giant penguin under the effect of an awaken spell.

Scrivenscry insists that the characters help it search for the Books of Keeping (see the “Scrivenscry and Kingsport” sidebar). If the characters engage Scrivenscry in conversation, Kingsport chooses a moment to approach the nearest character and pass a note to them. Scratched into a piece of leather are the words “Help me” in Common, which Kingsport wrote using his beak.

The characters must evade, defeat, or strike a deal with Scrivenscry if they want to rescue the penguin. If outmatched in combat, Scrivenscry teleports into the depths of the library and plots its revenge. Characters who agree to cooperate with the arcanaloth soon find themselves alone with Kingsport, who reveals that Scrivenscry is a cruel and wicked master. Neither Kingsport nor his master knows much about Ythryn, since they arrived only yesterday by using a spell scroll of plane shift.

Scrivenscry and Kingsport

Scrivenscry is a vainglorious arcanaloth who roams the planes in search of the_Books of Keeping_, four lost tomes that hold the true names of every yugoloth ever created. The fiend stumbled on Ythryn’s library by chance and is convinced that at least one of the legendary tomes is hidden here. Alas, Scrivenscry is mistaken.

Scrivenscry’s anxious penguin servant, Kingsport, was promised a life of enlightenment. The truth is that Kingsport was turned into Scrivenscry’s lackey, who lives in fear of his cruel, unpredictable master. The blind giant penguin hopes to be free of the arcanaloth one day.

Searching the Library

Characters who spend a few hours studying the books in the library learn 1d3 facts from the area Ythryn Lore table. One of the tomes they examine is an almanac that lists past winners of the city’s Chain Lightning tournament (see area area area Y3). Characters who read this tome find a summary of the game’s rules.

In addition, characters who search the library find a journal written by Thufeus, one of the few mages who survived Ythryn’s crash. It describes how the city fell from the sky and the attempts of its doomed survivors to escape (see “area The Fall of Ythryn"). The last entry reads “Iriolarthas is convinced that aid will come in time from Netheril. I am not so sure.”

Treasure

Scrivenscry carries three spell scrolls (Leomund’s tiny hut, plane shift, and wall of ice) and a chime of opening with a single use remaining.

Kingsport’s cart contains six texts that Scrivenscry deems valuable. Each one is a treatise on the Outer Planes and is worth 250 gp to a collector of such works.

Necropolis Locations (Y10-Y18)

Y10. Arboretum

A canopy of golden leaves crowns the trees inside a sunken basin. The trees grow in stark contrast to their bleak surroundings, their branches swaying even though the air is deathly still.

The grove is nestled in a hollow in the city floor. Vents spaced around its perimeter wall emit puffy gray vapor, which rises above the treetops and disperses as rain. An illusory hemisphere above the arboretum projects a false sky; now malfunctioning, the vista flickers between a wild storm and a vast field of stars.

Nether Oak

A tree called the Nether Oak grows at the heart of the arboretum. For centuries, Netherese mages crafted their wands and staffs from the wood of this oak. Saturated in profane magic, the tree developed a brooding sentience and a gnarly face. The Nether Oak uses the treant stat block but is neutral evil and speaks Common and Primordial.

When the characters arrive, the Nether Oak is in deep slumber. To complete the Rite of the Arcane Octad (see “area Rite of the Arcane Octad"), they must craft a wand from the wood of this tree. Gathering wood without waking the tree requires a successful DC 20 Dexterity (Stealth) check. If the characters wake the tree, they can convince it to part with some of its wood with a successful DC 15 Charisma (Persuasion) check, but only if it believes they intend to perform nefarious magic with it. The Nether Oak is easily angered and uproots itself if driven to combat. When it attacks, four Needle Blight spring from the ground to assist it, acting on the same initiative count.

Y11. Tower of Divination

The walls of this thin tower are etched with intricate designs of hands and eyes. Silver light flickers from a high window, above which a large, carved eye animates and blinks. Part of the tower’s roof is missing.

A detect magic spell cast here reveals an aura of divination magic. When the characters reach the top floor of the spire, read:

Large gashes in the roof allow you to see the dark, icicle-festooned roof of the great ice cavern beyond.

Silver light emanates from a three-foot-diameter glass orb situated atop a two-foot-high cylindrical stone plinth in the center of a thirty-foot-diameter, rubble-strewn circular chamber. Eyeballs drift inside the orb, like fish in a bowl. Some have cataracts, while others are bloodshot or pus-filled, but all turn and gaze at you as you approach.

Huge chunks of the walls have broken off in here, and the inscription bearing the divination passage from the Rite of the Arcane Octad is missing.

With a successful DC 10 Intelligence (Religion) check, a character recalls that a crystal ball filled with eyes is the symbol of Savras, god of divination.

Orb of Divination

The stone plinth upon which the orb rests is engraved with instructions written in Draconic: “Ask and we shall find.” To use the orb, one must place one’s hands on it and speak the name of an object or a person. If the target exists on the same plane of existence as the orb, the character touching the orb experiences a vivid vision of the target’s location and knows how far away it is and in what direction. Such insight, however, comes with a risk: a creature that receives a vision must make a DC 20 Constitution saving throw. On a failed save, the creature takes 10 (3d6) piercing damage as one of its eyes is magically plucked from its socket and teleported inside the orb (see “Injuries” in the Dungeon Master’s Guide for rules on losing an eye).

If asked for the whereabouts of the missing wall engraving needed to complete the Rite of the Arcane Octad (see “area Rite of the Arcane Octad"), the orb provides a vision of where it fell inside the observatory (area area Y15). The orb is magically anchored to this chamber and cannot be removed or destroyed. The only limit to how many times it can be used is how many eyeballs the party has remaining.

Y12. Wellspring of Answers

A deep well plunges through the city floor into darkness. Five crystal benches encircle it, glinting under the purple glow of a nearby street lamp.

The stone well is 100 feet deep and lined with slippery ice and frost, making it impossible to negotiate without climbing gear or magic. Months before Ythryn’s fall, a circle of mages known as the Telepathic Pentacle tried to fuse their minds together to become a conjoined telepathic force. The procedure went terribly wrong, and their bodies and minds melded into a single monstrosity. Iriolarthas imprisoned the thing in this empty well so that its latent telepathic powers could be tapped by the city’s elite. A short obituary is engraved around the lip of the well in Draconic: “Herein lie the immortal remains of the Telepathic Pentacle. Sit, meditate, and learn.”

Thing in the Well

A gibbering, five-headed aberration lies in a semiconscious state at the bottom of the well. The warped faces of the Telepathic Pentacle strain at the ends of its thick, undulating necks. The monster uses the hydra stat block, except that it has a climbing speed of 30 feet.

The monster shudders awake if a light source penetrates more than 80 feet into the well, or if a creature sitting on one of the benches awakens it (see below).

Meditation Benches

By sitting on these crystal benches and meditating, citizens of Ythryn could join their minds with the Telepathic Pentacle, gaining insights about their past and future. A creature that sits on the bench can, after 1 minute of meditation, gain one clue from the area Ythryn Lore table by making a successful DC 15 Wisdom (Insight) check. If the check fails by 5 or more, the creature’s wayward thoughts awaken the thing in the well. A creature can gain only one insight from the well per day, and only while the monster is alive.

Y13. Bazaar of the Bizarre

A large market hall sits at one end of this plaza, its four broken towers leaning inward. Faded pennants hang above the entrance, frozen stiff. A loud clatter resounds from within the hall.

This market hall once sold relics of arcane wonder. Now, its interior is a warren of mangled shop fronts crushed by chunks of ice and stone. Most of the wares have become worthless, and everything else has been destroyed by a headless iron golem that is presently rampaging around inside the building.

Without its head, the golem has the following changes to its statistics:

• The golem has 150 hit points (its hit point maximum). It has a challenge rating of 10 (5,900 XP).
• It is blinded and deafened, giving it disadvantage on all its attack rolls, and it can’t use its Poison Breath.

The golem was decapitated when Ythryn crashed into the Reghed Glacier. Its head wound up deep within the Caves of Hunger (see area area H9 in chapter 6), and its body has been stomping around Ythryn ever since. The golem swings blindly at anything that attacks it.

Y14. Hall of Silk

Silken drapes hang from the walls of this storefront, their surfaces swirling with illusory images of dragon’s fire and twinkling star fields. A group of emotionless figures stand guard outside, looking for all the world like frozen statues.

Six demos magen (see area appendix C) guard the entrance to this store. They attack anyone who tries to steal the silks on display (see “Treasure” below) but otherwise let strangers explore the store.

Inside the store, five galvan magen (see area appendix C) watch over rest of the merchandise. More of the magic silk hangs in long drapes throughout the interior, after being spun by four Phase Spider that lurk in the hall’s rafters. The spiders are enchanted to produce sorcery silk, a material with illusions woven into it that was fashioned into robes for Ythryn’s elite. Characters who enter the store spot the spiders immediately. The spiders defend themselves if attacked but are otherwise nonthreatening.

In the center of the interior, crystal mannequins draped in finery encircle an empty pedestal. If a creature steps onto the pedestal, an illusion of a magnificently dressed human flickers to life before them and introduces itself as Silksmith Mixyll. The illusion welcomes the guest to its emporium and explains the robe-making process. As it speaks, the phase spiders descend silently and use their legs to take the creature’s measurements before spinning the creature a tailor-made robe. As the robe is being fashioned, Mixyll urges its guest to “imagine any image your heart desires.” The spiders can, in the 10 minutes it takes to create the robe, spin any illusory design or effect into the garment. On completion, they drape the robe over the creature’s shoulders and ascend back to their lair. Each guest can gain this benefit only once.

Treasure

A silk robe spun by the spiders is worth 250 gp. If the characters ransack the store, they find ten other silk robes (250 gp each) that are on display and weren’t damaged when the city crashed.

Y15. Observatory

This conical tower is held relatively upright by a ring of arched buttresses. Expressionless humanoid figures stand in silence around it. The roof has a large, ragged hole in it where something large smashed through.

Three galvan magen, three demos magen, and one hypnos magen stand guard outside the observatory with orders to prevent strangers from entering it (see area appendix C for their stat blocks). The hypnos magen telepathically orders intruders to leave the area. Defying this order prompts the magen to attack.

The iron door at the base of the observatory is welded shut from the outside and must be broken down. It has AC 19, 30 hit points, and immunity to poison and psychic damage. A blue slaad lurks on the other side of the doorway and attacks as soon as the door ceases to be an obstacle. This slaad is hostile toward all other creatures and can’t be reasoned with.

Once inside, the characters can ascend the tower to its uppermost floor:

A large telescope dominates a thirty-foot-diameter circular chamber at the top of the tower. Gazing into the telescope’s eyepiece is a hulking, frog-like biped in wizard’s robes that pays you no mind as it mumbles to itself.

Adamantine shields cover the observatory’s windows. A large chunk of stone from another building has crashed through the roof and embedded itself in the floor like a jagged stone knife. This intruding fragment bears a strange inscription on one side.

By training the magic telescope on distant stars, Ythryn’s astronomers could summon alien creatures from those stars to be questioned, studied, or dissected. The fall of Ythryn damaged the telescope beyond repair, rendering it useless.

When Ythryn fell, a piece of the Tower of Divination (area area Y11) crashed through the observatory roof (see “Inscription” below). In the resulting chaos, the blue slaad encountered on the tower’s ground floor escaped from its cell and rampaged through the observatory. The Arch-Astronomer, who became infected by the slaad’s chaos phage, ordered her surviving apprentices to seal her inside the tower with the monster. In the years, decades, and centuries since, she has managed to keep the blue slaad from escaping through the hole in the roof.

The Arch-Astronomer, now a green slaad, is madly fiddling with the telescope, hoping to reverse its power so that it can project itself out of the tower to some faraway place where it can find happiness, but it has no hope of success. If the characters interrupt the Arch-Astronomer, it tries to frighten them away by baring its teeth and claws. If they touch the telescope or damage it further, the slaad goes crazy and attacks them. If they merely want to read the inscription on the wall fragment that crashed through the roof, the slaad leaves them alone.

Inscription

The chunk of wall from the Tower of Divination (area Y11) bears the following inscription in Draconic: “Third, a burnt palm loosens the tongue. Shed a secret about yourself for all to hear.” This is a passage from the Rite of the Arcane Octad (see “area Rite of the Arcane Octad” ).

Y16. Menagerie

An immense dome looms before you, its crystal roof marred by a web of cracks. Through the gaps in the building’s shell, and on the other side of the open entranceway, you see a strange landscape of miniaturized natural features.

This building’s entrance lies unattended. Ythryn’s mages would visit here to conjure up one-of-a-kind pets. Small-scale versions of natural habitats were constructed throughout the park: miniature mountain ranges, deserts, and forested streams, all now draped in ice. At the heart of this mixture of landscapes stands the machine that brought the menagerie’s creatures into existence.

Chimeric Creator

This device is a 10-foot-diameter iron wheel on its side, held above the ground by a metal brace, with eight barrel-sized, egg-shaped open containers attached to the outer ends of its spokes. The apparatus has a bronze control panel with a lever next to it. A character who spends at least 1 minute examining the device can make a DC 15 Intelligence (Arcana) check. On a successful check, the character gains an understanding of how to use it without knowing its purpose. To operate the device, 80 hit points of blood must be distributed evenly between its eight containers. Once the blood is properly deposited, pulling a lever causes the wheel to spin. The blood disappears 1 minute later, the wheel stops, and a creature crawls out of one of the containers. This creature is loyal to whoever pulled the lever. Determine the creature by rolling a d6 and consulting the Chimeric Creations table.

The chimeric creator needs 8 hours to recharge before it can be used again. A gauge on the device indicates how long it will take to recharge.

Chimeric Creations

Y17. Theater

The roof of this domed building is wrecked and open to the elements. Inside is a theater with a large stage, seating for more than one hundred, and a backstage area. Icicles hang from its sagging balconies, and rime-frosted masks leer and grin from its fractured walls.

A wooden writing desk sits in a backstage room, wrapped in chains and padlocked. A character using thieves' tools can try to pick the lock as an action, doing so with a successful DC 15 Dexterity check. In a leather-bound folder in one of the desk drawers are five scripts for a play called A Blasphemy of Kings. The play tells the story of five siblings, each expecting to claim the throne of their late father. As the protagonists try to prove their worth, it is revealed that they’re all in fact dead, having perished alongside their father in the cataclysmic event that destroyed their kingdom.

Cursed Play

Each script has a different cover showing a humanoid figure that represents one of the siblings: the Martyr (with a noose around its neck), the Traitor (with a knife held behind its back), the Bewitched (with a fairy whispering in its ear), the Haunted (with a demonic shadow terrorizing it), and the Fool (performing a handstand). Each of the five scripts is cursed. Anyone who spends an hour reading a script must succeed on a DC 18 Wisdom saving throw or become cursed. A creature cursed in this way is gripped by a sudden feeling of impending doom. Each of the five scripts imparts a different curse, which can be ended by a remove curse spell or similar magic:

• Martyr’s Script All attacks against the cursed character are made with advantage.
• Traitor’s Script The cursed character can’t perform any action that would directly benefit one of their allies.
• Bewitched’s Script The cursed character hears the voice of an imaginary fey creature whispering in their ear. Whenever presented with a choice, the character must randomly determine what action to take.
• Haunted’s Script A shadowy fiend plagues the cursed character’s dreams (or trances in the case of an elf), denying that character the benefits of a long rest.
• Fool’s Script The cursed character has disadvantage on all ability checks.

Y18. Tower of Necromancy

The remains of a toppled tower lie scattered around you. Its fractured base, protruding from the ground like a broken tooth, is teeming with crawling gray hands.

A detect magic spell cast here reveals an aura of necromantic magic. Two hundred Crawling Claw are tirelessly but ineffectively trying to excavate the tower’s ruins, brick by brick. Anyone who disrupts this effort is attacked by 2d6 claws. Deep under the rubble, the corpse of High Necromancer Cadavix lies crushed, yet his ghost remains behind to haunt the tower. Characters who linger in the area of the tower witness his gaunt spirit staring glumly down at the debris. Cadavix’s ghost is harmless and attacks only in self-defense; it laments the fall of Ythryn and longs to see its corpse freed from the ruins.

Excavating the tower requires pickaxes and shovels, and it takes a number of hours equal to 50 divided by the number of excavators (minimum 1 hour). The crawling claws don’t count as diggers, nor do they attack characters who join the digging effort. Quite the contrary: they get visibly excited as the unearthing of their master draws near. If Cadavix’s frozen corpse is unearthed, his spirit is laid to rest and the claws scuttle off into the ruins. Those who find the corpse can claim its necklace (see “Treasure” below).

Inscription

Characters who dig deep enough to reach Cadavix’s corpse also reach the tower’s foundations and uncover a section of wall that bears the following inscription in Draconic: “Seventh, trace a circle with the ashes of the dead.” This is a passage from the Rite of the Arcane Octad (see “area Rite of the Arcane Octad").

Treasure

Cadavix’s corpse wears a necklace of fireballs with six beads remaining.

Spire of Iriolarthas (Y19a-Y19h)

A shimmering force field surrounds this 1,200-foot-tall obsidian citadel, which rises from the center of Ythryn and dwarfs all neighboring structures. Creatures can’t pass through it, nor can they teleport to any location inside it. Any creature that performs the Rite of the Arcane Octad (see “area Rite of the Arcane Octad") near the spire can pass through the force field in either direction thereafter.

The spire, the interior of which is shown in map 7.3, has the following recurring features:

Demilich’s Lair. The spire is the lair of the demilich Iriolarthas. The lair actions noted in the demilich entry of the Monster Manual apply throughout the spire, though Iriolarthas can use lair actions only while inside it. The spire doesn’t have demilich lair traits.

• Ceilings. Ceilings are 30 feet high inside rooms and 10 feet high in corridors.
• Doors. Doors are made from enchanted oak fitted with adamantine locks and hinges.
• Lighting. The interior of the spire is brightly lit by continual flame spells cast in wall sconces.

Y19a. Main Entrance

If the characters reach this area by ascending the strut at area area Y6, read:

Near the apex of the strut, the ceiling of the tunnel gives way to a landing that offers a view of the citadel’s uppermost reaches. Light from a high window illuminates a set of steps that ascend to a pair of mahogany doors in the tower’s face.

The magic that once sealed the doors has long since faded away. When visitors approach the doors, a hypnos magen (see area appendix C) from area area Y19d appears at the overlooking window and uses its telepathy to politely instruct the intruders to leave the area. If the intruders behave threateningly or ignore its warnings, the magen tries to drive them away using suggestion spells, or failing that, attacks them.

Y19b. Ballroom

Chamber music washes over you as you enter this ballroom. In contrast to the desolate, frozen ruins outside, a dozen people mill around in here, dressed in flowing silk garments and holding colorful hand masks and feathered fans. Noble courtiers laugh and gossip as servants move among them, offering sugared treats on silver platters.

The music, people, food, decor, and warmth are illusions with which the characters can interact (see “Joining the Ball” below). The scene can be ended with a successful dispel magic spell (DC 19). If the illusory ball is dispelled, the room’s true contents are revealed:

The ballroom lies in ruins, rimed with ice, its furniture jumbled and shattered. Above the floor where nobles danced, three glass cylinders with iron fittings slowly move through the air. Housed in each cylinder is a swollen human brain floating in a bath of slimy, translucent goo.

Three Netherese wizards chose to continue their revels into undeath, each one becoming a brain in a jar (see appendix C). The three wizards have been driven mad by their undead existence. Dispelling the illusion drives them into a furious rage. Visitors who ruin the ball in any way are attacked.

Joining the Ball

The characters can interact freely with the illusory surroundings. The magic reacts to their actions, allowing them to hold conversations with courtiers, join the dance, or even sample the canapes. All the illusory figments know nothing of Ythryn’s fate and are interested only in revelry and gossip. Characters who spend at least 5 minutes talking to the illusory guests or servants learn one random fact from the area Ythryn Lore table.

Y19c. Council Chambers

These chambers served as offices for bureaucrats who ran the citadel’s day-to-day operations. Each room contains a single table, a cabinet filled with ruined parchment scrolls, and a dresser containing writing materials. Everything is in disarray and covered in ice.

Characters who search the northernmost chamber discover an unfinished letter that details the acquisition of an artifact dating back to the empire of Ostoria. This rune-carved stone spindle is described as having an unknown purpose. The writer notes that it has been moved to the citadel’s stasis chamber for further study.

Y19d. Guard Passage

At the end of the passage to the west, a narrow window overlooks the steps that lead to the main entrance (area area Y19a). Anyone who enters this passage is challenged by a hypnos magen (see area appendix C)—the same one that tries to shoo away intruders in area Y19a. This magen emerges from a cramped sentry chamber to the east and uses telepathy to politely inform intruders that they are trespassing: if the intruders don’t leave at once, the magen tries to forcibly eject them.

Y19e. Liquefaction Chamber

Shifting green, purple, and blue light spills into this room through a single window. Bolted-down tables hold an array of equipment: beakers of alchemical fluid, alembics, cut crystal needles, surgical tools, coiled leather tubes, and more. Behind the tables stands an ornate suit of armor. Where the head should be is a swollen human brain floating inside a canister of translucent fluid.

This ritual room is designed to serve a grisly purpose: the transformation of a living creature into a brain in a jar. Veneranda, a neutral evil Netherese wizard, extracted her own brain to become a brain in a jar (see appendix C) that is affixed to the body of a headless helmed horror. If the characters threaten or attack her, Veneranda turns the helmed horror against the group and attacks. Even though they are conjoined, the brain in a jar and the helmed horror roll initiative separately and attack as separate creatures. The brain can detach from the helmed horror as a bonus action.

Unlike her companions in the ballroom (area area Y19b), Veneranda is coldly calculating and fully aware of Ythryn’s fate. If the characters communicate with her, she greets them warily in Loross (see the “area Loross: The Netherese Tongue” sidebar) and tries to find out what has happened in the world in the centuries since Ythryn’s fall. Her singular goal is to restore Ythryn to its past glory. She doesn’t know why the city crashed, but she believes that the broken obelisk (see area area Y21) can turn back time to repair the damage. To activate its magic, Veneranda says she needs Iriolarthas’s staff of power, which he keeps in his study. She proposes that the characters break into Iriolarthas’s study, steal his staff, and bring it to her. She declines to accompany them, on account of the likely danger. If they complete this mission and return with the staff, she escorts them to the obelisk and tries to activate it. If the characters are unwilling to help Veneranda achieve her goal, they quickly outlive their usefulness, and she tries to destroy them.

Ritual of Brain Transfer

Veneranda can use the equipment in this chamber to transform one humanoid into a brain in a jar. This ritual takes 24 hours and results in the death and liquefaction of the subject’s body. Veneranda doesn’t allow anyone to view the ritual while it’s being performed.

Y19f. Staff Storage

This irregularly shaped room contains six staffs stored in racks along its walls, with room for more.

Each staff can serve as an arcane focus for a spellcaster. The staffs are as follows:

Staff 1 is a straight stick of pale ash with a stern-looking owl’s head carved into its top.

Staff 2 is a smooth, polished length of blue-tinted wood that’s as strong as steel, with black veins running through it and an octopus carved into its top.

Staff 3 is made of translucent purple glass, which splits into three branches at the top that circle around one another to form a hollow spiral with an orb of lighter purple glass tucked inside it.

Staff 4 is carved from golden laspar wood, with carvings of fish swimming upriver along its length.

Staff 5 is made of weirwood, a hardy substance similar to oak. Its shaft is gnarled and twisted, its top carved to resemble a human hand grasping a snake.

Staff 6 is made of chardalyn (see “Chardalyn”) and is suffused with Netherese magic. While holding the staff, a creature is immune to the frightened and poisoned conditions.

Y19g. Den

This chamber is affected by the same illusion that conceals the true nature of the ballroom (area area Y19b). If that illusion hasn’t been dispelled, read:

Courtiers lounge on luxurious cushions inside this circular chamber, smoking from long pipes and dining on fruit. Against the back wall is a large harp, its strings being plucked magically to fill the room with haunting music. In the middle of the room, a gem-studded, cubic wooden chest sits on a round marble table with an octopus-shaped base.

If the illusion is dispelled, the music ends and the chamber is revealed to be an abandoned, icy ruin. The chest and the table are real objects that remain after the illusion is dispelled.

Treasure

The chest is an abracadabrus) that Iriolarthas and his guests used to produce food and drink.

Y19h. Members' Bar

These rooms are affected by the same illusion that conceals the true nature of the ballroom (area Y19b). If that illusion hasn’t been dispelled, read:

Well-dressed revelers mill about, talking loudly to each other while servants carry bottles of wine and spirits around to refill their cups. Behind a rectangular counter, a bald, pale-skinned humanoid serves wine from an ornate bottle.

If the illusion is dispelled, this area is shown to be a frozen ruin bereft of inhabitants.

Treasure

Behind the rectangular counter, held in storage racks, are a dozen bottles of two-thousand-year-old wine. A detect magic spell reveals an aura of abjuration magic around each bottle, which has preserved its contents. Each bottle of wine is worth 50 gp to an interested buyer.

Spire of Iriolarthas (Y19i-Y19hq)

Y19i. Force Bridge

A 7-foot-tall, 4-foot-wide window at the north end of area Y19b overlooks a 35-foot-wide gap in the spire’s superstructure. On the far side of this gap, a similar window opens into the Chamber of Sorcery (area Y19j). Between these windows stretches a magical, invisible 5-foot-wide plane of force that serves as a bridge. (On map 7.3, this bridge is marked by a pair of dashed lines.) This invisible bridge, which is safe to cross, is suppressed by the activation of the spindle in area Y19n.

Y19j. Chamber of Sorcery

Your reflections dance over the mirrored surfaces of this chamber. Eleven alcoves extend from the walls like the points of a star, each one narrowing to a niche where a gently glowing crystal is mounted five feet above the floor. The air seems to hum with pent-up power.

Soon after the characters enter this area, an entity called Everlast makes its presence known. Everlast is a living spell bound to the spire. It can manifest in the image of any humanoid species or gender but defaults to the form described below:

Suddenly, the crystals brighten as rays of energy burst forth one by one to converge in the center of the room. As more of the rays intersect, a translucent figure comes into view where their light converges: a bald man wearing a long, purple gown. His face breaks into a smile as he sees you.

Everlast speaks the same language as any creature that converses with it. He can’t attack or be damaged, and he can’t be dispelled.

Iriolarthas created Everlast to aid him and his apprentices in their doomed mission to restore Ythryn from ruin. In the years since its creation, Everlast has seen Iriolarthas crumble into dust and his apprentices transform into nothics. With nothing to do except uphold his standing orders, Everlast has become hopelessly bored. The characters are the first new faces he has seen for centuries, and he immediately warms to them. Everlast’s standing orders are as follows:

• Assist in the city’s restoration.
• Do not reveal the city’s secrets to outsiders.

Everlast can manifest anywhere inside the spire and can move instantaneously between locations within it. If the characters express interest in restoring Ythryn to its former glory, he laments, “Many powerful minds have tried.” If the characters mention Veneranda’s plan to use Iriolarthas’s staff of power and the obelisk, Everlast cautions them by saying, “That might be unwise, for the obelisk was damaged in the crash. Iriolarthas was unable to repair it.” If the characters ask Everlast how to reach Iriolarthas’s study, he says he can’t help them, saying, “My orders prevent me from revealing the city’s secrets to outsiders.”

Energy Crystals

The crystals embedded in the niches are used to project Everlast’s illusory form throughout the spire. Each crystal is a Tiny object with AC 8, 3 hit points, and immunity to poison and psychic damage. If more than half of the crystals are removed or destroyed, Everlast ceases to exist.

Secret Door

This hatch is mounted in the ceiling, 30 feet above the floor, and can be spotted from the floor only with a successful DC 20 Wisdom (Perception) check. Knocking on the hatch causes it to swing open, revealing a 5-foot-diameter vertical shaft that ascends 50 feet to area Y19k. A character can use an action to pull open the hatch by force, doing so with a successful DC 20 Strength check.

Y19k. Dome

The following boxed text assumes that the characters arrive by moving up the shaft from area Y19j. Modify this text if the characters enter from the south:

You ascend into an oval hall glittering with frost. Carvings decorate the walls, and long icicles hang from the ceiling. A ten-foot-radius dome of translucent ice encloses the area around the shaft from which you emerge. At the far end of the hall, two blade-shaped patches of pitch darkness hover in the air to either side of a double door. A glowing green crystal roughly the size of a human fist is set into the arch above the doorway.

A hemispherical wall of force, its outside coated with a thin layer of ice, covers the shaft leading down to area Y19j. This barrier was created by a wall of force spell and is maintained by the glowing green crystal set above the doorway (see “Green Crystal” below). As long as this crystal is glowing, the wall of force can’t be dispelled.

Two living blade of disaster (see appendix C) guard the double door that blocks the way to area Y19l. The blades attack intruders that move in range of their blindsight (30 feet), and the blades can pass right through the wall of force.

Green Crystal

This glowing crystal sustains the wall of force but has become loose in its stone fixture. Whenever a loud noise is made inside the chamber, the loose crystal flickers. Tremendously loud noises, such as those made by a thunderwave spell or a horn of blasting, cause the crystal to go out for 1d6 rounds, during which time the wall of force is suppressed. The first time this happens, the ice that coats the dome collapses.

A character within reach of the crystal can use an action to pry it from its fixture, which causes the crystal to go dark for good, ending the wall of force. Destroying the crystal has the same effect. The crystal is a Tiny, 1-pound object with AC 13, 4 hit points, and immunity to poison and psychic damage.

Y19l. Testing Chamber

The following boxed text assumes that the characters look through the doorway from area Y19k. If they arrive from the south, modify the text accordingly:

Lining the far wall of this hall are eight doors, each marked with a different arcane symbol. On the wall above them is etched an inscription in Draconic.

A magical trap (marked T onmap 7.3) fills the 10-foot-square area immediately south of the double door to area Y19k and triggers whenever a creature that is neither a construct nor undead enters the area for the first time. Any creature that triggers the trap is targeted by a flesh to stone spell (save DC 17). A creature can’t set off the trap more than once. After it’s triggered three times, the trap vanishes.

Draconic Inscription

The inscription reads “Speak thy master’s name and enter.”

Eight Doors

A character who succeeds on a DC 10 Intelligence (Arcana) check recognizes that the symbols on the doors represent the eight schools of magic. Opening any of the eight doors reveals utter darkness beyond. A creature that has darkvision can’t see into or through this magical darkness, but a warlock with Devil’s Sight can. Magical light, as well as light created by spells of 8th level or lower, can’t illuminate it. This darkness fills the tunnels south of the doors and can’t be dispelled. To pass through safely, a character must speak the name of one of Iriolarthas’s eight apprentices and then step through the door associated with that wizard’s school of magic. The eight apprentices were:

| - | - | | High Abjurer Taruth | High Evoker Zadulus | | High Conjurer Damorith | High Illusionist Ajamar | | High Diviner Apius | High Necromancer Cadavix | | High Enchanter Ivira | High Transmuter Metaltra |

The characters can learn the apprentices' names from the museum (area area Y29). Each time a creature steps through a door without speaking the correct name, a barbed devil appears in the dark corridor beyond. The devil can see in the magical darkness and attacks any creatures that move into the corridor without first speaking the correct name. These devils can leave the darkness to pursue their foes. One minute after a devil appears, it disappears, leaving no trace of itself behind. Once a barbed devil has been summoned, no other devil can be summoned into that same corridor for 24 hours.

Y19m. Chamber of the Ebon Star

A vortex of glowing stars hangs in the air inside this chamber, slowly rotating on its axis. As the constellations move, they cast radiant starlight across the walls. Eight high-backed chairs, each bearing a different arcane symbol, face this starry miasma.

Iriolarthas’s apprentices, known as the Wizards of the Ebon Star, governed Ythryn from this hall. Eight magically darkened corridors connect this hall to area Y19l. Separate archways open into areas Y19n and area Y19o.

At the south end of the hall, a 10-foot-wide passageway leads to a locked double door, beyond which lies a balcony (area area Y19p). The door is warded with magic that prevents it from being damaged or forced open; it can be unlocked, however, by someone who uses the adamantine key in area Y19o, or by a character who uses thieves' tools and makes a successful DC 18 Dexterity check as an action to pick the lock.

Star Field

The swirling star field represents the cosmos as it was known to the Netherese. A character who studies the star field sees a strange phenomenon: a dark star in a position where no known star exists today. This character now risks being cursed with a foreboding sense of doom. At the end of the character’s next long rest, the character must make a DC 20 Intelligence saving throw. On a failed save, the character gains the following flaw: “I can’t look at the sky because the ebon star might be looking back at me.” Any magic that ends a curse can rid the character of this flaw.

Wizards' Chairs

Any character who succeeds on a DC 10 Intelligence (Arcana) check recognizes that the symbols on the chairs represent the eight schools of magic.

Anyone who has a supernatural charm gained by drinking from the goblet in area Y8 can sit safely in the chair for the school of magic tied to that charm. Similarly, a wizard can sit in whichever chair matches their chosen arcane tradition. (For example, if Vellynne Harpell is with the party, she can sit in the chair marked with the symbol of necromancy, since she is a necromancer.) If one or more party members take their proper seats here, the star field transforms into a glowing door that persists for 1 minute before transforming back into its original form. While in this room, Iriolarthas the demilich can use an action to cause the doorway to open without having to sit in a chair. Creatures that move through this door are teleported to the upper level of area area Y19q.

Each chair is a Medium object with AC 15, 18 hit points, and immunity to all damage except force damage. Destroying all the chairs causes the star field to disappear, cutting off access to area Y19q from this room.

Y19n. Stasis Chamber

A ten-foot-tall spindle of gray stone hovers upright and rotates slowly inside this circular chamber. All around it, the surfaces of the room’s walls are cracked, as though some terrible energy once coursed through them.

This chamber was built to house unstable magic items during experimentation, but it couldn’t contain the artifact that Iriolarthas and his apprentices retrieved from the bottom of the Sea of Moving Ice. During a routine examination, the spindle briefly became active, dispelled magical effects throughout Ythryn, and caused the city to plunge into the Reghed Glacier. The spindle is now dormant but can be reactivated to wreak havoc on the Weave.

The spindle is immune to all damage and is unaffected by any magic in existence today. It can’t be moved from this location. If it is targeted by a spell of 5th level or higher, an explosion of magical energy blasts from it: all magic items and magical effects within a three-mile radius (including those within the spire) are suppressed for 24 hours, and spellcasters are drained of any unexpended spell slots. Living spells, constructs, and other magically created creatures are unaffected. The pulse of energy suppresses magical traps throughout the city and causes the floating chamber above Skydock Spire (area area Y28) to crash into to the ground, pulverizing it and dealing 99 (18d10) bludgeoning damage to each creature inside it.

Y19o. Library

The walls of this roughly triangular room are filled with floor-to-ceiling bookshelves. Hundreds of books and scrolls were thrown free of their resting places when the city crashed and now cover the floor. Time and bitter cold have not been kind to them.

Most of the books and scrolls that litter the floor have been ruined by centuries of disuse, but adventurers who search the remains unearth two survivors: a scroll (see “Treasure” below) and a brittle tome with a black, eight-pointed star on its front cover. This brittle tome records the various meetings of the Wizards of the Ebon Star. One passage explains, in the Draconic script, that “Master Iriolarthas opens the door to his study when three or more of his apprentices—or those empowered by the goblet in the House of the Arcane—are seated correctly in the Chamber of the Ebon Star.” This passage provides adventurers with the information they need to open the magical doorway in area area Y19m.

Treasure

Lying among the ruined documents are two useful items: a scroll of the comet) and an adamantine key. The key is nonmagical and unlocks the double door to the balcony (area Y19p).

Y19p. High Court Balcony

A locked double door bars the way to area area Y19m. The door is warded with magic that prevents it from being damaged or forced open; it can be unlocked, however, by someone who uses the adamantine key in area Y19o, or by a character who uses thieves' tools and makes a successful DC 18 Dexterity check as an action.

The Wizards of the Ebon Star used this balcony to make proclamations to the inhabitants of Ythryn. Words spoken by a creature standing on the balcony are magically amplified to sound ten times louder than normal.

Y19q. Iriolarthas’s Study

This room can be accessed by activating the magic door in area area Y19m. The door is a two-way portal that snaps shut after 1 minute, though it can be reopened from this side by speaking the proper command word (“Saldrinar”). Anyone who arrives by this route appears on the room’s upper level, which the following boxed text assumes:

This large chamber has lain undisturbed for centuries. On the upper level, all around you, are tables covered with wizardly paraphernalia. A soft groaning sound emanates from a shadowy, door-sized rectangle along the curved northern wall.

Staircases to the east and west descend to the lower part of the room, where a sunken library is situated in a twenty-foot-wide, ten-foot-deep circular pit. A ladder running along a circular track inside this hole allows easy access to the many books and scrolls on its shelves.

If the characters have not yet encountered Iriolarthas, the demilich and three Nothic are present:

Perched on the edge of the pit are three aberrant creatures, each one staring at you with a singular, hideous eye. Floating above the middle of the pit is a human skull with wispy, arcane symbols forming above it.

Have the players roll initiative for their characters, and roll initiative for all the other creatures present.

See the “Iriolarthas the Demilich” section at the start of the chapter for information about the demilich. Iriolarthas attacks anyone who takes its staff of power or spellbook from atop the tables (see “Treasure” below). The nothics defend the demilich and themselves.

The shadowy, groaning rectangle on the north wall is a living demiplane (see appendix C) that was created when Iriolarthas escaped Ythryn’s fall. It moves toward the nearest intruder with the intent of trapping that creature into its extradimensional chamber. Anyone who is cast into this chamber must deal with five hostile creatures already trapped inside it: three galvan magen (see area appendix C) and two Flesh Golem. As the golems attack new arrivals, the magen use their Shocking Touch and Static Discharge actions to heal the golems' wounds.

The sunken library in the middle of the study has shelves lining its 10-foot-high walls and a ladder that can be pushed along a circular track to reach every shelf. Among the books and scrolls kept here is a bundle of parchment maps and schematics detailing aspects of Ythryn. Characters who study these papers for at least 1 hour learn the following facts:

• The city was held aloft by the Ythryn mythallar (area area Y23). Up to eight mages could attune to this device at one time. If all of them agreed, they could use its power to move the city through the skies or control the weather for miles around it.
• If disaster ever struck the city, the wizards could exploit the power of the obelisk (area area Y21) to turn back time and avert ruin. The schematics contain instructions for activating the obelisk, which requires a staff of power as a power source.
• The command word to reopen the magic door to area area Y19m is “Saldrinar,” which also happens to be the name of a long-dead Netherese archmage.
• The command word to deactivate the force field around the spire is “Olostin.” If this name is spoken aloud within Iriolarthas’s study, the force field surrounding the spire and the Ythryn mythallar (area area Y23) deactivates permanently.

Treasure

The following treasures can be found amid the rubbish on the upper level of the study: a small metal case containing four vials of quicksilver (500 gp each), an intricate crystal rod (1,800 gp), Iriolarthas’s fully charged staff of power, a hefty spellbook titled The Incantations of Iriolarthas, and a scroll of tarrasque summoning (see appendix D for descriptions of the spellbook and the scroll). The crystal rod and vials of quicksilver are nonmagical material components needed for the create magen spell in Iriolarthas’s spellbook.

Professor Skant is excited by the discovery of the scroll of tarrasque summoning, since the tarrasque is one of its areas of expertise. The professor orb knows all the tarrasque lore in the Monster Manual, as well as the monster’s traits, which it’s happy to share with the party.

Necropolis Locations (Y20-Y29)

Y20. Tower of Evocation

The top of this tower is shaped like an axe blade. Red light shines out from a slender window high overhead.

The tower’s interior is damaged by fire, lightning, and acid, having borne the brunt of centuries of destructive spellcasting. A spiral staircase ascends to the topmost chamber. When the characters arrive here, read:

Red orbs of light dance like fireflies around this thirty-foot-diameter octagonal chamber. A large unlit brazier stands in the center of the room, and eight ten-foot-square alcoves line the walls, each filled with ice. The arched ceiling is covered with icicles.

This chamber is lit by a permanent dancing lights spell that can be dispelled (DC 17). Characters who succeed on a DC 10 Wisdom (Perception) check spot an inscription on the ceiling, but the ice covering it renders it unreadable (see “Inscription” below).

The central brazier is enchanted. A single spark created inside it causes it to blaze with magic flames for 24 hours. If the brazier is lit, the heat it gives off starts to melt the ice in the chamber, revealing the words of the inscription after 10 minutes.

Alcoves

Examination of the alcoves reveals that each one contains what appears to be a 10-foot cube of ice. One of the cubes has a humanoid skeleton—the remains of High Evoker Zadulus—suspended inside it. These blocks of ice are, in fact, eight Gelatinous Cube held in magical cryostasis. If the brazier is used to thaw the ice in the room, these cubes awaken after 10 minutes and emerge from their alcoves, attacking all other creatures in the room.

Inscription

The inscription on the ceiling is written in Draconic and reads “Fifth, quench the flame in thy palm with ice.” This is a passage from the Rite of the Arcane Octad (see “area Rite of the Arcane Octad").

Y21. Obelisk

A sixty-foot-tall obelisk of black stone, its surface covered in arcane runes, projects from the ground. A thin crack has formed on one side, stretching from the obelisk’s base to its middle.

Before Ythryn crashed, Iriolarthas relied on this obelisk as a precautionary measure in case Ythryn experienced a catastrophe. It was one of a few rare Netherese artifacts that could rewind time (see the “Secret of the Obelisks” sidebar). It was damaged during Ythryn’s fall and, despite Iriolarthas’s best efforts, the demilich could not repair it. Characters who learn about the obelisk in Iriolarthas’s study (area area Y19q) know how to activate it (see “Activating the Obelisk” below).

A character who examines the obelisk and succeeds on a DC 10 Intelligence (Arcana) check recognizes that the magic runes inscribed on the obelisk represent all eight schools of magic. If the check result exceeds the DC by 5 or more, the character also identifies runes relating to chronomancy, the art of magically manipulating time.

Activating the Obelisk

If the characters retrieved Iriolarthas’s staff of power and Veneranda is with them, she insists that the staff be used to activate the dormant obelisk. Any character who succeeds on a DC 20 Intelligence (Arcana) check can verify that this task is not beyond the staff’s power, although it would take at least half of the staff’s charges to accomplish. If a creature attuned to the staff uses an action to expend 10 or more of its charges while touching the staff to the obelisk, power surges from the staff and triggers the following devastating events:

• The staff splits in half, triggering its Retributive Strike property (see the staff’s description in the Dungeon Master_’s Guide_).
• Any creature within 120 feet of the obelisk that isn’t killed by the staff’s explosion becomes 10 years younger. Creatures whose age is reduced to 0 by this effect wink out of existence, leaving behind the items they were wearing or carrying.
• The obelisk disintegrates, as do other obelisks like it throughout the world, but not before hurling the entire planet into the past, to a time prior to the fall of Ythryn (see “area Year of Chilled Marrow").

Secret of the Obelisks

In this adventure, we learn the secret of the obelisks that have appeared in other fifth edition adventures published by Wizards of the Coast, including Tomb of Annihilation and Waterdeep: Dungeon of the Mad Mage.

The first group of these magical obelisks was crafted by a secret society of spellcasters called the Weavers. These obelisks could alter reality on a grand scale, sending a region or an entire world back to an earlier time (effectively erasing part of history). The obelisks were constructed to counteract the effects of calamitous spells and cataclysmic events.

An evil wizard named Vecna stole one such obelisk and used it to erase the obelisk’s creators from existence. Vecna also stole the knowledge needed to create new ones. That knowledge later came into the possession of Netherese wizards, who built similar obelisks of their own. They believed that if some catastrophe destroyed their empire, these obelisks could help restore it. Unfortunately for them, most of the obelisks built to protect Netheril were stolen or otherwise lost over time, as were records of their purpose and information about how to activate them.

Y22. Tower of Illusion

An obsidian tower shrouded in gossamer mist soars before you. Eyes carved into the stonework appear to fixate on you as you approach the entrance. The spire’s highest window emits a purple light.

A detect magic spell cast here reveals an aura of illusion magic. This magic makes the eyes carved into the tower appear to follow those who approach the structure. Characters who enter the tower find the mist inside as well. Haunting sounds fill the air: heartbeats, sobbing, and ragged, gasping breaths.

As the party advances, the mists around the characters manifest into illusions of their worst fears, and each character becomes the target of a phantasmal killer spell cast at 8th level (save DC 17). Characters who survive the experience emerge together in the tower’s upper chamber, which is free of mist.

Chamber of Illusion

The tower’s uppermost chamber is 30 feet square and lit by purple continual flame spells in wall sconces. An inscription written on the walls in Draconic reads “Sixth, show thy face to the sky.” This is illusory script masquerading as a passage from the Rite of the Arcane Octad (see “area Rite of the Arcane Octad"). If the characters leave after acquiring only this information, they hear the faint laughter of Ythryn’s High Illusionist, Ajamar, trailing behind them as they exit the tower. The real passage is revealed when the illusory script is successfully dispelled (DC 17) or examined by someone who has truesight. It reads “Sixth, hide thyself behind a mask.”

Y23. Ythryn Mythallar

This enormous artifact is enclosed within the force field surrounding the Spire of Iriolarthas. To reach it, a character must first perform the Rite of the Arcane Octad (see “area Rite of the Arcane Octad") to lower the force field.

Beneath the great spire, a luminous fifty-foot-diameter crystal sphere rests on an ornate stand.

See appendix D for a description of the Ythryn mythallar and its magical properties. The first time a creature tries to attune to the mythallar, its meditation is disturbed by the arrival of a tomb tapper (see appendix C), which tunnels up from belowground to attack anyone present. The tomb tapper fights to the death to defend the Ythryn mythallar.

Unless Iriolarthas is destroyed, the demilich is already attuned to the mythallar. If Iriolarthas senses that another creature is trying to use the mythallar, it always disallows the attempt and flies to the mythallar’s location to discourage any further tampering with the device. Only by destroying the demilich can the characters use the mythallar’s properties unimpeded. The mythallar’s power to control the weather can undo the everlasting winter that Auril has cast over Icewind Dale (see “Epilogue”).

Y24. Tower of Enchantment

Ice has engulfed the lower floors of this crumbling tower. Pink light pours out of the highest window—a single point of illumination in a dark and out-of-the-way region of the city.

A detect magic spell cast here reveals an aura of enchantment magic. The interior walls are covered with the following sentence in Draconic crudely written with pitch over and over: “All work and no play make Ivira a dull girl.” The floor is strewn with pitch-covered buckets and mops frozen stiff by the cold.

As the party explores higher up in the tower, the recurring phrase changes to: “I am Ivira. Ivira is my name.” These words are written in wine stains, and the floor is littered with empty wine bottles.

Painted in blood above the door leading to the uppermost chamber are the words “The crown knows all!” in Draconic. When the characters enter the topmost chamber, read:

An elderly woman sits rigidly on a black throne, shrouded in ice. She wears a crown of entwined iron tentacles, and her forehead is bruised where the band fits tightly against her skull. An inscription decorates the wall behind her.

This chamber is lit by pink continual flame spells flickering in sconces.

At the height of her power, the archmage Ivira wore a magic crown to shield her mind against mental attacks. When Ythryn crashed and magic was momentarily undone, Ivira’s crown became corrupted and began to siphon away her memories. She has endured centuries as a husk of her former self, kept alive by the magic of her crown. In her current state, she is stunned.

A character who succeeds on a DC 12 Wisdom (Medicine) check can tell that Ivira is still alive. Her crown is cursed (see below). Removing it from her head causes Ivira to shudder and shed the ice that has formed around her. With the crown gone, her body rapidly deteriorates, as the centuries take their toll. Ivira has only a few seconds before she dies and turns to dust; with her dying breath, she implores the characters in Loross (the dead Netherese tongue) to “destroy the crown… release my memories… let me have peace.”

Cursed Crown

Ivira can’t remove the crown from her head. Any other creature that touches it must succeed on a DC 17 Wisdom saving throw or become charmed by it and use its next action to don the crown. If the saving throw succeeds, the creature is immune to this effect of the crown for the next 24 hours.

From the moment it is donned, the crown begins to siphon memories from its wearer, starting with its earliest memories. The wearer can sense that its memories are being stolen but can’t remove the crown from its head except within an antimagic field.

After wearing the crown for 1 hour, a creature must succeed on a DC 15 Intelligence saving throw or be stunned until the crown is removed from its head by someone else. This saving throw is repeated at the end of each hour until either the crown has been removed or its wearer has become stunned. If a creature wears the crown for ten uninterrupted days, the condition becomes permanent, as the crown reduces its wearer to a mindless husk. A greater restoration spell or similar magic ends the effect and restores the creature’s lost memories.

The crown can be destroyed on the anvil of disjunction (area area Y4). It is otherwise impervious to damage. If the crown is destroyed, the memories it has absorbed flood over all creatures within 10 feet of it. Characters assailed by this barrage gain 1d6 pieces of lore from the area Ythryn Lore table.

Inscription

The inscription on the wall behind the throne is written in Draconic and reads “Fourth, coax a secret from another.” This is a passage from the Rite of the Arcane Octad (see “area Rite of the Arcane Octad").

Y25. Hall of Weightless Wonder

Four basalt columns support a huge mirrored dome on which are reflected Ythryn’s tallest spires and the cavern’s vast stalactites.

Ythryn’s elite used this hall for meditation. As someone floated around inside the dome, an illusory image of the person went on with their daily affairs elsewhere in the city.

The four supporting columns have doors in their bases, which open into shafts that ascend to the dome. The shafts are 60 feet long and lit from above by the shifting auroral light of the dome’s interior. A character who steps inside a column levitates up to the dome in 1 round. When a character reaches the dome, read:

The interior of the dome is illuminated by a swirling miasma of colors. Frozen human figures float in the air, cross-legged and serene.

Creatures in the dome gain a flying speed of 30 feet and can hover. The corpses of a dozen Netherese apprentices hover around this area, with their hands on their knees and their eyes closed. Characters who adopt this position can meditate by succeeding on a DC 12 Wisdom check. While meditating, a character can cast the project image spell (save DC 15). The spell lasts for 1 hour, and a character can perform the meditation once per day. To leave the dome, a character must stand at the top of one of the four shafts, to be transported down in a manner similar to how they arrived.

Y26. Tower of Transmutation

A tower rises before you, straight as an arrow. A faint light shines from in the spire’s highest window, and hairline cracks creep up its walls like ivy.

The cracks covering the outside of the tower were caused during the crash, when the magic protecting the tower strained to keep it from collapsing.

Describe the interior of the tower as follows:

The tower’s interior walls are sculpted with impressions of humanoid forms pressing out from within—clawing hands and howling faces, captured in stone forever.

As Ythryn was about to fall out of the sky, High Transmuter Metaltra used a true polymorph spell to transform herself into something she thought would survive the city’s destruction: an adamantine statue. An hour later, when the spell should have ended, nothing happened. Through no fault of her own, she had become a statue permanently. Only a wish spell can restore her, and then only briefly as she ages centuries in a matter of seconds.

Characters who climb to the tower’s peak find the statue of Metaltra lying in a corner. The statue depicts a woman in a wizard’s robe, posed as if she is completing a spell. As her statue was being thrown about during the crash, it damaged part of an inscription on one wall.

Inscription

The damaged inscription is a passage from the Rite of the Arcane Octad (see “area Rite of the Arcane Octad"). Written in Draconic, it reads “Eighth, stand firm in thy circle of death and consume——.” The missing word, destroyed by Metaltra’s statue, is “poison.” Characters who search the room for stone fragments can’t find the pieces they need to identify the missing word, but casting a mending cantrip on the wall repairs the damage and reconstructs the missing word. If the characters don’t have access to the mending cantrip, a divination spell or similar magic can be used to learn the missing word.

Treasure

Adventurers who search the uppermost chamber find a bag of beans in a small pile of rubbish.

Y27. Music Hall

This enormous, boot-shaped structure is capped with three pipes that resemble the arteries of a titanic heart. Tall doors open into the structure’s dark interior.

Old posters are plastered to the outer walls of this music hall. Anyone who can read the Draconic script can translate the poster closest to the entrance: “Experience the Netherese Esoteric Orchestra’s masterwork, The Dark Between the Stars!” A character who succeeds on a DC 15 Intelligence (History) check knows this legendary piece of music, as does any bard in the party. If the characters enter the music hall, read:

This grand music hall is aglitter with ice, and the floor underfoot is strewn with the crystal shards of fallen chandeliers. The frozen corpses of the audience lie strewn among the tiered seats, their expressions frozen in rapturous adulation. On the stage, cadaverous musicians slump over their shattered instruments.

The Netherese Esoteric Orchestra was midway through its crowning performance when Ythryn fell from the sky. Determined to finish, the musicians played on as the city hurtled to the ground, but Ythryn crashed before they could finish. Deprived of the opportunity to complete their grand finale, the orchestra’s troubled spirits haunt the hall.

A conductor’s baton rests on a lectern at the front of the stage. If a character grasps the baton, the hall echoes with the sounds of instruments being tuned, and a spectral orchestra materializes from out of the corpses onstage. The ghostly musicians hold their instruments and stare expectantly at their conductor. These spirits can’t be turned or harmed in any way.

Conducting the Orchestra

To conduct the orchestra through the end of their final symphony, a character must succeed on three consecutive DC 15 Charisma (Performance) checks made 1 minute apart. A character who knows The Dark Between the Stars gains advantage on each check.

On the first successful check, the orchestra launches into a hauntingly beautiful performance. If the next check succeeds, listeners experience a falling sensation in the pits of their stomachs, mirroring Ythryn’s downward plunge, as the music reaches a crescendo. If the third and final check succeeds, the conductor brings the piece to a satisfying close as the sound of ghostly applause rises from the audience and phantasmal black roses rain down on the musicians, who face the audience and bow before fading into the afterlife. A character who successfully conducts the orchestra gains inspiration.

On each failed check, the spirits become angry, and their antipathy toward the conductor deals 27 (5d10) psychic damage to each creature in the music hall.

Y28. Skydock Spire

A tower more than one hundred feet tall has a rotating glass chamber hovering above its ruined summit. Four pointed pillars clutch the chamber’s walls, giving it the appearance of a colossal floating crown.

Skydock Spire stands 120 feet tall, and the glass chamber magically floats 30 feet above it. The chamber slowly rotates clockwise. The tower and the chamber are all that remain of a much larger facility that served principally as a dock for flying ships.

Characters who enter the tower see a staircase coiling around its interior walls. From atop the ruined roof, a character using rope can make a successful DC 15 Strength (Athletics) check as an action to catch onto the rotating chamber, which is a 40-foot-diameter room made of glass that offers a panoramic view of the city. This chamber once served as an opulent and intimate meeting place for the upper echelons of Ythryn’s society. Now it lies in ruin, with entrances lying open and the furnishings inside smashed.

Treasure

Characters who sift through the debris on the floor of the chamber find a miniature Netherese skycoach in a bottle (750 gp) and a nonmagical wand (a possible spellcasting focus) made of chardalyn (see “Chardalyn”). It is suffused with evil magic. While grasping the wand, one feels an urge to inflict terrible harm upon others, but the urge is easily resisted. Prolonged custody of the wand might have a more detrimental effect, at your discretion.

Y29. Museum

A palatial hexagonal building rises before you, crowned with a glittering domed roof. A double door on one side stands slightly ajar.

Characters who venture inside the museum find that statues and other objects of art have fallen from their plinths and lie in broken shards across the floor, and centuries of exposure have ruined most of the paintings that hang on the walls in elaborate frames.

Lower Level

Six Nothic are searching the lower level of the museum for relics. When they detect the entry of intruders, they converge on them and attack out of hunger.

Upper Level

Characters who ascend the stairs to the upper level come across the following display:

Suspended from the ceiling of a spacious fifty-foot square antechamber is the glittering, frost-covered corpse of a thirty-foot-long aberration shaped like a funnel, resembling an anemone. A tooth-filled maw at the wider end is surrounded by rubbery cilia, and around it dangle four limp, spindly appendages, each one ending in a clawed hand. At the opposite end of the body is a tail with a stinger.

A frost-covered plaque is bolted to a pedestal nearby, and the entire display is framed by four stone pillars that are, oddly, frost-free.

The pillars are four Spitting Mimic (see appendix C) that guard the creature on display, attacking anyone who touches or otherwise disturbs it.

The dead creature is a magically preserved phaerimm suspended from the ceiling by a dozen strong wires. If the characters wipe away the frost on the plaque, they can read what it says about the phaerimm in Draconic:

Adult Phaerimm—do Not Touch!

Dwellers of the Underdark, phaerimm are malevolent aberrations that are master spellcasters and highly resistant to magic. They use their telepathy to control the weak-minded. They strive to erase all other beings from existence and are known to have caused the collapse of the sarrukh empire of Isstosseffifil. They use their tail stingers to inject their eggs into alien hosts.

Iriolarthas and His Apprentices

Characters who proceed farther into the upper floor can see the museum’s domed ceiling, which is still intact and a sight to behold. It depicts a powerful mage standing on a balcony of the enclave’s central spire, addressing a sea of Netherese citizens below, who stare up at the figure, cheering. This is an image of Iriolarthas at the height of his power, magically preserved in stained glass that glows with its own arcane light. Eight large portraits adorn the walls beneath the dome, depicting Iriolarthas’s eight apprentices, known as the Wizards of the Ebon Star. The portraits hang 20 feet above the ground, and a frost-covered plaque is fixed to the wall just beneath each one. The faces in the portraits are depicted as looking up toward their master, Iriolarthas, with expressions of respect. Characters who clear the ice from the plaques can learn their names: High Abjurer Taruth, High Conjurer Damorith, High Diviner Apius, High Necromancer Cadavix, High Evoker Zadulus, High Illusionist Ajamar, High Enchanter Ivira, and High Transmuter Metaltra.

Dealing with the Arcane Brotherhood

In this chapter, two wizards of the Arcane Brotherhood attempt to realize their grand ambitions: Vellynne Harpell and Avarice. Both are described in area appendix C.

If the characters are having trouble solving a puzzle in Ythryn, such as how to deactivate the force field around the Spire of Iriolarthas, you can use Vellynne or Avarice to help them. Both NPCs are highly intelligent and can help the characters arrive at a solution. You, as the DM, can use them to keep the adventure from grinding to a halt.

Both Vellynne and Avarice will do almost anything to obtain Iriolarthas’s spellbook, and they are only slightly less determined when it comes time to choose who gets Iriolarthas’s staff of power, the scroll of the comet, and the scroll of tarrasque summoning.

If the characters helped Dzaan’s simulacrum become a real person in chapter 2 (see “area Lost Spire of Netheril"), he might be present as well. Without a full complement of spells, Dzaan isn’t nearly as helpful as Vellynne nor as dangerous as Avarice, but he’s just as greedy and self-serving. Roleplay him accordingly.

Vellynne’s Help

Vellynne Harpell can use her comprehend languages spell to translate passages of Draconic script found throughout the necropolis, and her Leomund’s tiny hut spell conjures an excellent refuge against the extreme cold. She tries to be as useful as possible while staking claim to her fair share of whatever treasure is found in Ythryn. She is particularly interested in magic items, especially those of a wizardly bent (such as Iriolarthas’s staff of power).

Vellynne’s Fall

If the characters part ways with Vellynne for any reason, she tries to explore Ythryn alone and contracts the area arcane blight. The next time the characters see her, she is either partially or fully transformed into a nothic.

Avarice’s Arrival

Avarice (see area appendix C) follows the characters through the Caves of Hunger to Ythryn, killing any NPCs they left behind to guard the caves. The albino tiefling wizard is joined by her two Gargoyle, her raven familiar, twenty Cult Fanatic (members of the Knights of the Black Sword), and ten roped Mountain Goat (see appendix C) that the cultists use for food and to set off traps. If Huarwar Mulphoon and Fel Suparra are alive, they are among the cult fanatics (see area area C6 for more information about these NPCs).

The Knights of the Black Sword speak Common and Infernal, and they have the following additional trait:

Icy Doom

When the cultist dies, its corpse freezes for 9 days, during which time it can’t be thawed, harmed by fire, animated, or raised from the dead.

Avarice and her retinue enter the necropolis 12 hours after the party arrives. Avarice immediately claims the floating chamber above Skydock Spire (area area Y28) as her base of operations, using her fly spell to reach it, while the cult fanatics encamp around the base of the tower. Avarice’s goal is simple: conquer Ythryn and claim its treasures for herself.

From her refuge, Avarice divides her expedition into four hunting parties of five cult fanatics each, and sends them off to explore the ruins, using her raven familiar and the gargoyles as aerial scouts. The party can meet Avarice’s minions anywhere in the necropolis (including inside the spire if the force field surrounding it is deactivated or suppressed). They have orders to attack the characters on sight.

Each time the party explores a new building, there is a 20 percent chance that one of Avarice’s hunting parties is already inside or arrives while the party is searching its interior.

Old Rivalries Die Hard

If she becomes aware of Vellynne’s presence in Ythryn, Avarice uses her raven familiar to deliver a written invitation to her rival, asking Vellynne to join her inside her floating lair. Vellynne accepts the invitation unless the characters strongly discourage her from doing so. There, Avarice coldly lays down her terms: abandon the necropolis within the hour. Conflict between members of the Arcane Brotherhood is forbidden, but Avarice makes it clear she is willing to ignore the rules if nobody lives to find out. When Vellynne leaves the meeting, Avarice sends her familiar out to spy on her rival and see if her demands are met, which Vellynne has no intention of doing.

Avarice as an Ally

Avarice is smart enough to ally with the characters if doing so might help her conquer Ythryn, but she won’t join forces as long as Vellynne Harpell is with them—she demands that they cast out her hated rival. If the characters oblige and banish Vellynne from their ranks, Avarice reciprocates by sharing 1d4 pieces of Ythryn lore she has learned (determine each piece by rolling on the area Ythryn Lore table).

Unlike Vellynne, who accompanies the characters, Avarice prefers to remain in her glass chamber atop Skydock Spire and stay in touch with the characters remotely by using her Rary’s telepathic bond spell. Once the characters find all the inscriptions they need to bypass the force field around the Spire of Iriolarthas, Avarice emerges from her base and accompanies them into the tower, eager to claim the treasures inside.

Auril’s Wrath

The Frostmaiden likes to preserve beauty by freezing it. If the characters failed to defeat Auril in chapter 5, she takes umbrage with anyone who unseals and plunders the necropolis of Ythryn. After the party has spent one day inside the city, Auril pays Ythryn a visit.

Please review the information about the Frostmaiden in appendix C before running encounters with her.

The Frostmaiden’s Forces

When the Frostmaiden arrives in Ythryn, the temperature throughout the necropolis drops by several degrees. Auril is joined by three Frost Giant Skeleton (see appendix C), six Snow Golem (see appendix C), and a pack of six Winter Wolf. After sending her skeletons, golems, and wolves into the city in small groups to kill interlopers on sight, Auril shuts down the force field around the Spire of Iriolarthas by sheer force of her divine will and watches over the city from its high balcony (area area Y19p). The force field remains deactivated until the last of Auril’s forms is destroyed or until she leaves the spire.

Any of Avarice’s minions still patrolling the city are swiftly captured and dragged before the Frostmaiden. Auril murders each captive in turn and transforms the cultist into a coldlight walker (see appendix C). These undead horrors venture out into the necropolis to hunt down the living.

Final Showdown

If the characters defeat most of Auril’s minions, the god’s cool voice echoes across the city from the high balcony of the Spire of Iriolarthas, demanding that they leave Ythryn or face her wrath. One hour after making this announcement, Auril leaves the tower and prowls through the streets in search of the characters. For every hour that passes, there is a 20 percent chance that she catches up with them. Only characters who flee the city and return to Icewind Dale are spared her wrath.

Summoning the Tarrasque

Characters who find the scroll of tarrasque summoning in the Spire of Iriolarthas might be sorely tempted to use it. Professor Skant, an expert on the tarrasque, warns the characters about the uncontrollable nature of the monster and the danger it represents, but the professor orb also confesses that it would love to observe the tarrasque firsthand.

If summoned in Ythryn, the tarrasque destroys everything in sight before smashing its way through the Caves of Hunger and continuing its rampage across Icewind Dale, inevitably putting Ten-Towns in peril. The mountains to the south, the sea to the north and west, and the towering glacier to the east contain the tarrasque for a while. The extreme cold also makes the creature lethargic. It might take months, but the hungry tarrasque eventually makes its way southward through the mountain pass, imperiling the rest of the Sword Coast, if nothing is done to curtail its rampage.

If summoned on Auril’s island, the tarrasque is trapped there by the deep, churning Sea of Moving Ice. The behemoth lays waste to Grimskalle and everything else on the island before sinking into a deep hibernation. Auril, if she survives, is forced to abandon her island lair and find a new refuge.