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The Handy Haversack

Level 4: Twisted Caverns

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Designed for four 8th-level characters, this level of Undermountain contains enough XP to advance such a group halfway to 9th level. The Twisted Caverns feature an aboleth, which is a legendary monster. Review the “Aboleth” entry in the Monster Manual before running this level of the dungeon to help you run the monster effectively.

What Dwells Here?

Control of this level is contested between an aboleth and a tribe of kuo-toa. The drow of House Auvryndar watch this conflict intently, waiting to see who comes out on top before making any push of their own. Various other Underdark species vie for a place in these caverns.

Aboleth

Illuun the aboleth, along with its pet chuuls and enslaved troglodytes, has taken over the lake cavern (area area 16) and pushed the kuo-toa out. Its presence has tainted the underground river, killing off fish and other river dwellers that provide sustenance to the kuo-toa. Illuun plans to take over the entire level as a step toward gaining control of Undermountain and then Waterdeep.

The aboleth rarely leaves its watery lair and relies on its servants to capture new slaves.

House Auvryndar

A drow contingent led by a drow priestess of Lolth has holed up in area areas 11 and area 12. These forces report to T’rissa Auvryndar on level 3 and are preparing to challenge whoever perseveres in the conflict between the aboleth and the kuo-toa. These drow control access to one of the magic gates on this level.

Kuo-toa

The kuo-toa on this level were pushed out of the lake cavern (area area 16) and away from their nesting caves (area area 24) by the aboleth. They have taken refuge in area areas 20 and area 21 while the kuo-toa archpriest, Noolgaloop, creates an idol of a new god. The archpriest hopes the god will come to life and destroy the aboleth. Noolgaloop is using random items and the body parts of various creatures to craft the idol.

The kuo-toa don’t trust drow and attack them on sight, but they tolerate non-drow adventurers who agree to help bring Noolgaloop’s vile god to life or are willing to face the aboleth in battle.

Fungi

The northwest caves (area areas 1 through area 7) hold numerous species of fungi. Many of these fungi are edible or have useful properties. Species of fungus found on this level and elsewhere in Undermountain include the following.

Barrelstalk

A barrelstalk is a cask-shaped fungus that can be tapped and drained of the water inside it. A single barrelstalk contains 1d4 + 4 gallons of fresh water. Its husk provides 1d6 + 4 pounds of food.

Bluecap

Dubbed “the grain of the Underdark,” a bluecap is a tall, slender mushroom with a bright blue, bell-shaped cap. Although bluecaps are inedible, their spores can be ground to make a nutritious, bland flour. Bread made from bluecap flour is known as sporebread or bluebread. One loaf is equivalent to 1 pound of food.

Ripplebark

This shelf-like fungus resembles a mass of rotting flesh, but it’s surprisingly edible. Though it can be eaten raw, it tastes better roasted. A single sheet of ripplebark yields 1d4 + 6 pounds of food.

Timmask

Known as “devil’s mushroom,” a timmask is a 2-foot-tall toadstool with orange and red stripes across its beige cap. Uprooting or destroying a timmask causes it to expel a 15-foot-radius cloud of poisonous spores. Creatures in the area must succeed on a DC 14 Constitution saving throw or be poisoned. While poisoned in this way, a creature is under the effect of a confusion spell with a duration of 1 minute. When the spell effect ends, the poisoned condition also ends.

Trillimac

A trillimac is a mushroom that grows to a height of 4 to 5 feet and has a broad, gray-green cap with a light gray stalk. The cap’s leathery surface can be cut and cleaned for use in making maps, hats, and scrolls; its surface takes on dyes and inks especially well. The stalk can be cleaned, soaked in water for an hour, then dried to make a palatable food akin to bread. Each trillimac stalk provides 1d6 + 4 pounds of food.

Tongue of Madness

A tongue of madness looks like a large human tongue. Although it is edible, it holds no nutritional value. A creature that eats this fungus must succeed on a DC 12 Constitution saving throw or compulsively speak aloud its every thought for the next hour. The effect can be ended with a lesser restoration spell or similar magic.

Zurkhwood

A zurkhwood is a mushroom that can grow up to 40 feet high. Its large, grain-like spores are edible (one specimen provides 1d4 + 4 pounds of food), but the fungus is more important for its hard and woody stalk. Zurkhwood is one of the few sources of timber in the Underdark; it is used to make furniture, containers, bridges, and rafts, among other things. Skilled crafters can use stains, sanding, and polishing to bring out different patterns in a zurkhwood stalk.

Exploring This Level

The following locations are keyed to map 4. A tributary of the Sargauth River called the River of the Depths enters Undermountain here and flows down to level 5.

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(Player Version)

Unless otherwise noted, all tunnels on this level are 20 feet high, and caverns are 30 to 50 feet high. Most of the floors on this level are uneven and covered in dirt and bat guano. Because of this soft ground, Wisdom (Survival) checks made to track creatures on this level are made with advantage.

1. Fungus Forest

Fungi. Mossy paths run between patches of stout trillimac and a forest of towering zurkhwood whose caps scrape the 40-foot-high ceiling.

Clearings. Throughout the cavern are small clearings where the fungi have been torn out of the mossy ground.

Characters who search for tracks and succeed on a DC 10 Wisdom (Survival) check find several large, bare footprints made by the ettin who regularly feeds on the mushrooms in this cavern.

2. Jibber-Jabber

Ettin. An ettin inhabits this dripping cave.

Stalactites. Needle-sharp stalactites stud the 30-foot-high ceiling.

Fungi. Barrelstalk, bluecap, and ripplebark fungi grow in irregular patches throughout the cavern.

The ettin’s heads are named Jibber and Jabber, and they get along well—an unusual state of affairs for an ettin. This situation might be the result of the ettin’s having a comfortable home and all the food it could desire. The ettin also has a friendly neighbor in the Alchemist (see area area 4), who provides Jibber-Jabber with compost that transforms the water in barrelstalk mushrooms into mead. The only thing Jibber-Jabber is missing in its simple life is treasure to ogle. If the characters offer it 50 gp or more in coins, gems, and shiny art objects, the ettin allows them to pass through its domain and even harvest some fungus if they please. Jibber-Jabber might also impart the following useful information.

  • “Spider people” (drow) are living in the caves to the east. They are new neighbors.
  • The “fishy folk” (kuo-toa) and the “stinky lizards” (troglodytes) seem troubled and are moving about more than usual. (The ettin has not yet encountered the aboleth and knows nothing about its conflict with the kuo-toa.)
  • The water in the river has started to taste bad. (The ettin has not yet been poisoned by the water, which the aboleth has tainted with its presence.)

If the characters look like they could use more help, the ettin suggests they talk to the Alchemist and points them eastward. Jibber-Jabber describes the Alchemist as “smart, handsome, and small, but with a big smile.”

3. Death from Above

Fungi. Gardens of barrelstalk, bluecap, timmask, and trillimac fill the cavern. Between the garden patches meander paths that lead to and from the various exits.

Piercers. Stalactites cover the ceiling of the wide tunnel that leads south (to area area 5). Eight Piercer lurk among them.

Any character who searches for tracks along a path can make a Wisdom (Survival) check. On a check total of 20 or higher, the character finds the back-and-forth tracks of several bugbears, a troll, and a hook horror.

Characters who have darkvision or light sources bright enough to illuminate the ceiling can avoid piercer drops by steering clear of the stalactite formations, and attempts to do so are automatically successful. If no such attempts are made, a single piercer drops on the first light-carrying creature to cross the cavern. Whether it hits or misses, this piercer can’t attack again until it makes the long, slow climb back to the cavern ceiling. After the first piercer drops, avoiding the cavern’s stalactite formations becomes a simple matter.

4. The Alchemist

In this cavern, a green slaad posing as a human alchemist makes its home. Its lair has the following features:

Gourds. The walls are set with shelves at various heights. They hold numerous gourds, most of which contain failed alchemical elixirs.

Stone Block. A rough-hewn block of stone in the middle of the cave serves as a table. It is covered with a set of alchemist’s supplies.

Almost a year ago, the green slaad was drawn to Undermountain, deprived of its control gem, and set loose by Halaster. It has explored several levels of the dungeon in its quest to find the gem. For now, it has adopted the guise of a scatterbrained, shabbily dressed young man who has, for reasons he would rather not divulge, set up an alchemist’s lab in this cave. The slaad refers to itself only as “the Alchemist” and claims to have been kidnapped by Halaster from someplace it can’t remember.

The Alchemist bargains with creatures for materials it needs, trading potions for fungi and equipment. What it’s really looking for is its control gem, which it senses is close by (see area area 21a). It doesn’t want help finding the gem, though, for fear that the treasure might fall into the hands of those who try to control the slaad. If the characters obtain the gem and return it to the Alchemist, it cheers, turns invisible, and flees with the gem.

If the characters seem interested in knowing more about the Twisted Caverns, the slaad warns them about the ropers in area area 6. Also, it has struck up a friendship with the “two-headed giant” in area area 2 and urges the characters to speak with it, since it has lived on this level for a long time.

Potions for Sale

The Alchemist is happy to trade potions for supplies. For one potion, it demands 20 pounds of edible fungi and five tongues of madness (which characters can harvest from the surrounding caves), plus 50 gp worth of adventuring gear. The Alchemist has no use for coins, gemstones, art objects, or magic items. Each time the characters pay the Alchemist a visit, it has one of each of the potions described below available to trade. Each potion is a common magic item. It keeps these potions on its person, and a sneaky character can try to pilfer one with a successful Dexterity (Sleight of Hand) check contested by the slaad’s Wisdom (Perception) check.

Potion of Comprehension

When you drink this potion, you gain the effect of a comprehend languages spell for 1 hour. This liquid is a clear concoction with bits of salt and soot swirling in it.

Potion of Watchful Rest

When you drink this potion, you gain the following benefits for the next 8 hours: magic can’t put you to sleep, and you can remain awake during a long rest and still gain its benefits. This sweet, amber-colored brew has no effect on creatures that don’t require sleep, such as elves.

5. Cave of Crystals

Xorn. Three xorn feast on crystals near the western edge of the cavern, while harmless bats flutter below the 30-foot-high ceiling.

Difficult Terrain. A thick mix of mud and bat guano covers the ground. Treat this area as difficult terrain.

The xorn protect their crystalline food source. If a xorn loses more than half its hit points, it disengages from combat on its next turn and sinks into the floor, never to return.

Treasure

Once the xorn are defeated, the characters can retrieve forty fist-sized crystals worth 10 gp each.

6. Tangled Ropes

Ropers. This 30-foot-high cave holds a forest of stalagmites, some of which are broken. Two Roper lurk among them and ambush anyone who happens by.

Uneven Floor. The uneven floor is strewn with bits of chewed-up armor and bone, as well as the occasional copper piece or silver piece.

Treasure

Each roper has 1d4 gemstones (100 gp each) lodged in its gizzard, which characters can cut open once the roper is dead. They can also gather up a total of 32 cp and 11 sp scattered across the floor.

7. Mad Wizard’s Retreat

A human wizard, the lone survivor of an expedition to the Underdark, has taken refuge in this 30-foot-high cave. The cave contains the following:

Light. Phosphorescent moss growing in patches on the walls dimly lights the entire cave.

Fungi. Gardens of barrelstalk, ripplebark, timmask, and tongue of madness grow throughout.

Mage. Near the north wall, a slight woman wearing tattered gray robes over black pants sits on a 2-foot-tall toadstool. Her long black hair is tied back with a swatch of gray cloth that matches her robe. A quasit in toad form sits on her knee.

Darribeth Meltimer

The woman is Darribeth Meltimer (CG female Chondathan human mage, with the darkvision spell cast on herself and prepared instead of suggestion). A former adventurer, she was driven insane by contact with demons in the Underdark. A greater restoration spell or similar magic is needed to restore her sanity, without which Darribeth suffers from hallucinations and paranoia. If the characters approach her in a calm manner, Darribeth smiles and says to the toad on her knee, “Look, Teeha! I told you they’re not demons. I wonder if Urgala sent them.”

Darribeth desperately wants to get back to her wife Urgala, whom she hasn’t seen in a decade. When last they were together, Urgala and Darribeth were living in Amphail, a town north of Waterdeep. In the intervening years, Urgala moved farther north to the frontier town of Triboar, where she took over a modest inn called Northshield House. (See the adventure Storm King’s Thunder for more information on Urgala Meltimer and her inn.)

If her sanity is restored, Darribeth becomes her normal self—a curious and kind woman with a flair for magic who doesn’t mind bending rules for the greater good. She speaks Common, Dwarvish, Halfling, and Undercommon.

Darribeth has a rope of climbing that belonged to a colleague who perished in the Underdark. She offers it as payment for getting her back to the surface. In addition, if any wizards are among her rescuers, she lets them copy spells from her spellbook (see “Treasure” below).

Once restored to her right mind and borne safely to Waterdeep, Darribeth makes plans to return to Amphail. There, she learns what became of her wife and reunites with Urgala in Triboar. If the characters make the journey with Darribeth and all is well at Northshield House, Urgala is so delighted by their act of kindness that she offers them free room and board for as long as the inn remains standing. Urgala and Darribeth remain lifelong friends of the characters henceforth.

Quasit

Darribeth’s memory is fuzzy on where and when she met her talking toad during her Underdark exploits. The quasit, which Darribeth calls Teeha, has not revealed its true form to her. In the form of a toad, it torments her with false hopes of escape before dashing them. It has told Darribeth, for instance, that hezrou demons are nearby to keep her from leaving this cavern. If attacked or exposed, the quasit turns invisible and flees.

Treasure

Darribeth’s spellbook contains the following spells: cone of cold, counterspell, darkvision, detect magic, fireball, fly, greater invisibility, ice storm, jump, mage armor, magic missile, misty step, shield, suggestion, tongues, and water breathing.

In addition to her spellbook, Darribeth carries a backpack missing a strap, within which she keeps material components for her spells, a pouch containing 11 gp, a dagger, a canteen, and a worn blanket. Fastened to the backpack is a coiled rope of climbing.

8. Crossroads

The ceiling of this 30-foot-high cavern is studded with stalactites, and the floor is so uneven that it counts as difficult terrain. A search of the cavern reveals nothing dangerous or valuable.

9. Alarm System

Sloped Roof. The ceiling is 30 feet high at the northwest end of the cave and gradually slopes down to 20 feet high as the cavern narrows into a passage that leads to area area 10.

Tripwires. The uneven rock floor is dotted with small stalagmites, between which run nearly invisible trip wires made of webbing. These web strands set off hidden rockfall traps.

The driders in area area 10 have strung thin web strands between some of the stalagmites, creating trip wires. Any creature that enters a square marked T on the map has a 50 percent chance of breaking a strand and triggering a trap that releases rocks from a hidden crevice in the ceiling. If a trap triggers, all creatures occupying the trapped square must succeed on a DC 14 Dexterity saving throw or be struck by a falling rock for 5 (1d10) bludgeoning damage. In addition, the sound of the falling rocks alerts the driders in area area 10.

A character adjacent to a trapped square or in a trapped square can spot the trip wires with a successful DC 17 Wisdom (Perception) check, then track the thin webs to the point in the ceiling where the rocks are hidden. Once it is spotted, a rockfall trap can be disabled with a successful DC 12 Dexterity check by a creature in the trapped square; failing this check triggers the trap.

Tunnel to Expanded Dungeon

If you want to expand the dungeon north or east of here, assume that the tunnel in the north wall is hidden behind a 1-foot-thick wall of rocks held in place by web netting and clay mortar; characters can detect the false wall with a successful DC 10 Wisdom (Perception) check and break through it with ease.

10. Drider Lair

Driders and Spiders. The northern half of the cave is home to two Drider and five Giant Spider. The driders hide in the natural alcove north of the entrance, while the spiders crawl amid thick webs that fill the top 10 feet beneath the 30-foot-high ceiling.

Hidden Arch. The southern half of the cave is filled with thick, sticky webs. (These webs conceal an arch embedded in a wall at the south end of the cave. The arch is not visible from the cave entrance because of the webs concealing it.)

The driders while away the days carving zurkhwood figurines and writing poems on the caps of trillimacs in Undercommon. A sample haiku is presented below.

My Queen of Spiders,

Dark diamond of the Abyss,

Snare me in your web.

Arch Gate to Level 6

A character entering the cave through the arch gate automatically becomes stuck in the webs (see “Dungeon Hazards” in chapter 5 of the Dungeon Master’s Guide).

Carved into the arch are six stone niches, each one containing a small stone figurine that weighs 1 pound. The figurines represent a black dragon, a unicorn, an umber hulk, an owlbear, a minotaur, and a manticore. Carved into the wall inside the arch is a stylized image of a mountain with a full moon symbol above it. Close inspection of the moon reveals a half-inch-diameter hole in the middle of it.

The arch is one of Halaster’s magic gates (see “area Gates"). Its rules are as follows:

  • If the horn of the unicorn figurine is inserted into the hole in the moon symbol, the gate opens for 1 minute. None of the other figurines have protrusions that fit in the hole.
  • Characters must be 9th level or higher to pass through this gate (see “area Jhesiyra Kestellharp"). The first creature to pass through the gate triggers an elder rune (see “area Elder Runes").
  • A creature that passes through the gate appears in area area 27 on level 6, in the closest unoccupied space next to the similar gate located there.

Treasure

One drider has a set of calligrapher’s tools. The other drider carries a set of woodcarver’s tools and three carved zurkhwood statues of Lolth (1 gp each).

11. Drow Outpost

The drow of House Auvryndar established this outpost after discovering the arch gate in area area 11c. All told, this area contains a drow priestess of Lolth named Melith Auvryndar, a female drow mage named Thirza Helviiryn (Melith’s consort), two female drow elite warriors named Balryn and Talafaere, and four male drow named Altonrel, Kalanszar, Rezz, and Tsabalin.

11a. Main Cavern

Drow. Two male drow (Altonrel and Rezz) and a female drow elite warrior (Balryn) stand watch atop a ridge of natural rock in the middle of this 30-foot-high cave.

Fungi. Barrelstalk and ripplebark grow in small gardens around the ridge.

Provisions. Stacks of supplies and gear neatly line the walls, while a small iron pot sits on stones in one alcove.

If the characters enter in a nonthreatening manner, the guards are cautious but willing to summon their leaders to speak on their behalf. If greeted with hostility, the drow elite warrior sounds the alarm with a single whistle, bringing reinforcements from area areas 11b and area 11c. If the battle is not going their way, a second whistle brings the Quaggoth from area area 12b.

Treasure

Balryn wears an obsidian scarab bearing the insignia of House Auvryndar (25 gp).

The supplies stored in this cave include a set of carpenter’s tools, a set of leatherworker’s tools, five sets of manacles, and enough rations to feed one humanoid for 90 days or the entire drow contingent (including the drow in area area 12a) for 9 days.

11b. A Little Privacy

Drow. Melith, a drow priestess of Lolth and the leader of this outpost, meditates and prays before a shrine of Lolth while her consort, the drow mage Thirza, sits at a zurkhwood desk reading her spellbook.

Furnishings. The cave contains two sleeping pallets and a zurkhwood chest. A skewered darkmantle cooks over a spider-shaped bronze brazier filled with flaming coals.

If she had her way, Melith would launch a full-scale assault on the kuo-toa, wipe them out, and then deal with the aboleth. As things are, she relies on her sister, T’rissa Auvryndar (see level 3), for soldiers, and T’rissa does not support such a strategy. So, armed with only a small force, Melith has been forced to watch and wait as the aboleth and the kuo-toa plot to annihilate one another.

Melith is happy to let adventurers meddle in the war between the aboleth and the kuo-toa. If the characters approach her peacefully, she suggests a temporary—but mutually beneficial—alliance. Melith knows that the only route between this level of Undermountain and the next one down is the underground river. If the characters slay the aboleth or the kuo-toa archpriest and return to her with proof of its demise, Melith promises to furnish them with a raft that they can use to navigate the underground river and continue their descent through Undermountain. Such a raft is stored in area area 14, and Melith makes good on her promise.

Though she has great affection for Melith, Thirza sees any alliance with the characters as an opportunity to elevate herself in the eyes of Melith’s mother, Vlonwelv. After Melith concludes her business with the characters, Thirza prepares and casts a sending spell to contact Vlonwelv. She warns Vlonwelv that Melith has released a group of adventurers from her custody instead of killing them. After thanking Thirza for the information, Vlonwelv curses her daughter’s foolishness and awaits the adventurers' arrival.

Treasure

The drow priestess wears two silver bracelets set with onyx (25 gp each). She carries a flask of wine and the key to the room’s zurkhwood chest, which contains 500 gp. The lock on the chest can be picked with a successful DC 15 Dexterity check using thieves' tools, or opened with a knock spell or similar magic. Melith’s shrine contains a 1-pound obsidian figurine of the demon goddess Lolth in spider form (25 gp) and eight sticks of incense (5 gp each). Each stick burns for up to 8 hours and emits a sickly odor.

Thirza carries a spell scroll of gaseous form in a waterproof zurkhwood tube, 25 pp in a spider silk pouch, and her spellbook, which has black leather covers traced with webs of gold. The book contains the following spells: alter self, cloudkill, Evard’s black tentacles, fly, greater invisibility, lightning bolt, mage armor, magic missile, misty step, sending, shield, sleep, spider climb, web, and witch bolt.

11c. Arch Gate to Level 2

Drow. Two male drow (Kalanszar and Tsabalin) and a female drow elite warrior (Talafaere) rest here.

Arch Gate. An archway is set in the back wall and carved with images of falling coins. A thin slot is carved into the arch’s keystone.

Pallets. Six pallets lie spread out in the room.

The arch is one of Halaster’s magic gates (see “area Gates"). Its rules are as follows:

  • Feeding a gold coin into the keystone’s slot causes the coin to disappear and the gate to open for 1 minute. Other coins placed in the slot disappear but don’t open the gate.
  • Characters must be 6th level or higher to pass through this gate (see “area Jhesiyra Kestellharp"). The first creature to pass through the gate triggers an elder rune (see “area Elder Gates").
  • A creature that passes through the gate appears in area area 5 on level 2, in the closest unoccupied space next to the identical gate located there.
Treasure

Talafaere wears an obsidian scarab bearing the insignia of House Auvryndar (25 gp).

12. Bat Cave

The drow and their quaggoths recently expanded into this cavern, which is home to hundreds of bats.

12a. Drow Sentinels

Sloped Roof. The ceiling here is 50 feet high but slopes down to 30 feet high toward the southeast.

Drow. Natural shelves and narrow ledges line the walls, ranging in height from 10 to 30 feet. Hiding in the shadows atop 10-foot-high ledges are two male Drow Elite Warrior (Ryld and Llauzdrar).

Bats. Harmless bats flutter around, disturbed by the drow’s presence.

Stumps. The floor is dotted with the stumps of felled zurkhwood stalks and the occasional bat carcass impaled by a drow crossbow bolt.

Ryld and Llauzdrar have taken to shooting bats with their crossbows. Intruders provide the drow with a welcome opportunity to hone their melee combat skills. If a battle turns against them, Ryld and Llauzdrar use darkness spells to cover their withdrawal to area area 8. From there, they head to area area 11a to make their stand. These drow aren’t interested in conversation. If captured, however, they agree to lead their captors to area area 11 to speak with the drow priestess who commands them.

Treasure

Each drow elite warrior wears an obsidian scarab bearing the insignia of House Auvryndar (25 gp).

12b. Zurkhwood Bridge

Crevasse. A 20-foot-wide, 40-foot-deep crevasse splits the floor. Spanning the gap is the rotting trunk of a zurkhwood fungus.

Quaggoths. Living on natural stone shelves inside the crevasse are eight Quaggoth that serve the drow.

The quaggoths can climb the crevasse without having to make an ability check, as can other creatures with a natural climbing speed. A successful DC 10 Strength (Athletics) check is needed otherwise.

Moving across the trunk without slipping or falling requires a successful DC 10 Dexterity (Acrobatics) check. On a failed check, the creature slips and falls prone on the makeshift bridge—but on a check that fails by 5 or more, the creature plunges into the crevasse.

13. Zurkhwood Grove

Ceiling. This immense cavern is 50 feet high.

Fungi. A forest of zurkhwood erupts from the guano- and moss-covered floor, the tallest and oldest standing over 40 feet tall. Between the towering fungi lie a few toppled zurkhwoods, as well as several stumps.

Monsters. Near the edge of the forest, feeding on a duergar carcass, is a lone carrion crawler. The deeper forest is guarded by four awakened zurkhwoods (use awakened tree statistics).

A svirfneblin druid inhabited this grove until a few months ago, when he felt threatened by the arrival of the aboleth and decided to follow the River of the Depths back down into the Underdark. Before he left, the druid cast awaken spells on seven zurkhwoods in the grove, three of which have since been felled by duergar axes and damage-dealing spells. The four that remain are indistinguishable from normal zurkhwoods while they remain motionless. The awakened zurkhwoods try to kill or drive off creatures that cause harm to the grove. They understand Gnomish but can’t speak it.

The duergar, Iktarve Unsuttir, came up the river with some companions to cut down zurkhwoods and sell the wood—but he didn’t count on the grove’s fighting back. He was killed by the awakened zurkhwoods and left behind. The duergar’s scale mail is not salvageable.

The carrion crawler plans to spend the next several hours quietly devouring its meal. It attacks creatures that come within 10 feet of the dead duergar, but otherwise the crawler just wants to be left alone.

Treasure

A search of Iktarve’s corpse and the surrounding area yields a war pick, three javelins stuck in a felled zurkhwood, and an empty lapis lazuli flask (50 gp).

A thorough search of the grove accompanied by a successful DC 15 Wisdom (Perception or Survival) check reveals the gnome druid’s old hovel: an igloo-like mound of hardened bat guano. Inside, characters find a ratty old blanket hiding two Potion of Healing in stoppered gourds. The awakened zurkhwoods attack characters who loot the druid’s abandoned home.

14. Drow Rafts

Darkmantles. Stalactites hang from the 30-foot-high ceiling. Two Darkmantle disguised as stalactites remain motionless until they attack.

Rafts. Leaning against the west wall are two 10-foot-square rafts made of zurkhwood logs lashed together with thick spiderwebs. Resting nearby are six 10-foot poles that the drow use to guide the rafts.

Although the darkmantles need to eat, they flee if reduced to half their hit points or fewer.

The drow use the rafts to ply the River of the Depths. Each raft is built to carry six Medium humanoids and their gear, though as many as twelve people can fit onto a raft if push comes to shove.

15. Slippery Slope

Stench. A rotting stench fills this 30-foot-high cavern.

Slimy Corpses. The slime-coated floor slopes toward an underground river. Lying in the slime are the putrid corpses of three kuo-toa and four troglodytes.

Aboleth Projection. As the characters make their way along the tunnel leading west, an aboleth crawls out of the water and confronts them. This aboleth is a magical projection created by Illuun to intimidate the characters.

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Illuun the aboleth can sense the characters' presence and creates a magical projection of itself to interact with them. The projection lasts for as long as the aboleth maintains concentration, as if concentrating on a spell. Although the projection is intangible, it looks, sounds, and moves like the aboleth.

Illuun can sense, speak, and use telepathy from the projection’s position as if the aboleth were present at that location. If the projection takes any damage, it disappears. The aboleth has had unpleasant dealings with adventurers in the past and maintains a healthy fear of them. It uses the projection to warn characters that it will not tolerate incursions into its domain and urges them to withdraw or face extermination. It suggests the characters take the south passage to the river, then follow the current down to Wyllowwood (level 5). It’s happy to let them descend to lower levels of Undermountain, for it plans to conquer those levels eventually itself.

If the characters seem adamant about pressing deeper into the aboleth’s lair, Illuun telepathically commands the eighteen Troglodyte in area area 24 to circle around behind the characters (using the passage that enters area area 15 from the south) while it keeps the characters engaged in conversation. At the same time, it calls the three Chuul from area area 16 to come at the characters from the west, trapping them in the tunnel. As soon as the chuuls and the troglodytes arrive and begin their attack, the aboleth projection disappears.

16. Grotto of Madness

Illuun the aboleth has turned this flooded cavern into a den. The cavern is also defended by three chuuls that are under the aboleth’s sway.

The water varies in depth from 20 to 50 feet, and the cavern’s domed ceiling is 30 feet higher than the water’s surface. The walls are coated with slime but have abundant handholds. A successful DC 15 Strength (Athletics) check is required to climb them.

16a. Lost Island of Bulba-Slopp

Rising out of the water is a rocky island upon which the kuo-toa raised a shrine to their old god:

Chuul. Circling the island’s perimeter is a chuul that attacks anyone who sets foot on the island.

Petrified Otyugh. In the middle of the island, wearing a crude net as a cloak, is a petrified otyugh that the kuo-toa adopted as a god and named Bulba-Slopp. Treasure has been piled around the statue’s three stumpy legs.

Before the kuo-toa arrived, this island was inhabited by an otyugh. Halaster turned it to stone and lured kuo-toa to the grotto, knowing that the insane fish folk would come to worship the petrified otyugh as a god. The kuo-toa named it Bulba-Slopp, and it served as their god until the aboleth came on the scene. After Bulba-Slopp failed to protect the kuo-toa, the archpriest Noolgaloop set out to craft a new god, and Bulba-Slopp was worshiped no more.

Treasure

Piled around the petrified otyugh’s feet are 3,300 cp, 670 sp, and 350 gp.

The net draped over the otyugh is woven with worthless shells and bones. Tied to the net are two trinkets (roll twice on the Trinket table in chapter 5 of the Player’s Handbook), a rusty gauntlet, a leather boot, and an amulet made of composite wood and iron. The boot and the amulet are both magical:

  • The boot is one of two boots of elvenkind. A single boot is useless without its companion. The matching boot was swept downriver and eventually found by a goblin werebat named Vool (see area level 5, area 17).
  • The amulet controls the wandering shield guardian on level 1 (see “area Shield Guardian"). A rune on the back of the amulet matches a similar rune on the construct.

16b. Lake of the Aboleth

Monsters. Illuun the aboleth and two Chuul lurk in the water, which is dark, slimy, and fouled by the aboleth’s presence.

Underwater Tunnel. A 10-foot-high, 20-foot-wide underwater passage connects this cavern to area area 16c.

The aboleth and the chuuls prefer to fight underwater. In addition, the aboleth makes use of lair actions on this level of the dungeon. Although the aboleth wants more slaves, preserving its own life is more important. If its chuul bodyguards are killed, the aboleth telepathically summons the two chuuls from area area 17 as it withdraws to area area 16c, where it makes its final stand.

The water in the northeastern half of the cave plunges to a depth of 50 feet. As one travels toward the southwest wall, the lake’s depth shrinks to 20 feet.

16c. Treasure Trove

An underwater passage leads to this 30-foot-high cave. The water here is slimy and fouled by the aboleth’s presence, and every surface of the cave is covered in slime.

A kuo-toa whip and two kuo-toa stand guard atop a pebbled beach strewn with dead crabs, rotting fish, and treasure. These kuo-toa have been magically enslaved by the aboleth. While enslaved, the kuo-toa remain in constant telepathic contact with the aboleth, but they can’t take reactions. Whenever an enslaved kuo-toa takes damage, it can make a DC 14 Wisdom saving throw to break free of the aboleth’s control. On a successful save, the kuo-toa flees to the underground river by the shortest route and hides there.

Treasure

A thorough search of the beach yields 600 gp, a copper goblet (1 gp), a tarnished and dented silver pitcher (5 gp), a rotted leather bracer inset with three peridots (500 gp each), and a corked bottle containing a spell scroll of magic weapon.

17. Pick and Chuuls

Slimy Water. This cave and the adjoining tunnels are flooded to a depth of 10 feet with slimy water fouled by the aboleth’s presence.

Chuuls. Two chuul hide in the murky water. If the chuuls are defeated, an aboleth enters the cavern from the northeast passage. This aboleth is a magical projection created by Illuun to frighten away invaders. (This projection is like the one in area area 15.)

Rusty Pick. The walls and the 30-foot-high ceiling are coated in slime. A rusty miner’s pick is stuck in the west wall just above the water line.

The miner’s pick can be pried loose with a successful DC 13 Strength (Athletics) check. It has no special properties and is in poor condition.

18. Slimy Alcove

Slime. The floor of this damp alcove is 7 feet above water level, and every surface is coated in slime.

Damaged Rowboat. At the back of the alcove is a rowboat with a 1-foot-diameter hole in its hull. (A mending cantrip can repair the boat, which is large enough to hold four characters and their gear. The boat’s oars are missing, however.)

19. Beachhead

This slimy beach is littered with dead crabs and fish (killed by the aboleth-tainted water). Characters who search the beach also find two fishing nets left here by the kuo-toa.

20. Kuo-toa Refuge

Slime. Every surface of this 30-foot-high cave is coated in slime.

Kuo-toa. Two Kuo-toa Whip, twenty adult kuo-toa, and ten young kuo-toa (Small noncombatants) reside here. One whip stands watch by the river while the others rest on pallets. All the kuo-toa are poisoned from eating bad fish.

Caltrops. Caltrops made of sharpened bones lie scattered along the river’s edge. (The caltrops are meant to discourage the aboleth from beaching itself in the cave. Characters can easily spot and avoid them.)

The presence of the aboleth has tainted the underground river and poisoned its fish. Lacking an alternative food source, the kuo-toa have been eating the fish out of necessity, which has poisoned them. In their condition, the kuo-toa fight only in self-defense.

If the characters approach the kuo-toa in a friendly manner and offer them food or relief, the kuo-toa whips lead them to the archpriest Noolgaloop in area area 21a.

21. Archpriest’s Chambers

These caves are coated in slime.

21a. Making a God

Kuo-toa. Noolgaloop, a kuo-toa archpriest, is building a statue in the middle of this 30-foot-high cave while two Kuo-toa Whip stand perplexed.

Rotting Corpses. Mutilated monster carcasses piled around the room’s perimeter exude a putrid stench.

Noolgaloop is unwaveringly committed to reclaiming its holy shrine (area area 16), when the wiser course of action would be to lead its fellow kuo-toa to a new home far away from the aboleth and its servants. If the characters try to speak with the archpriest in a language other than Undercommon, Noolgaloop casts the tongues spell so they can converse. It demands that the characters help it complete the statue by retrieving the following items:

  • The legs and fur of a giant spider, to be fashioned into wings
  • Enough wood to build a chariot (a large raft or a zurkhwood mushroom would suffice)
  • A weapon worthy of a kuo-toa god

If the characters refuse to help, the archpriest deems them agents of the aboleth and tries to kill them with the help of its bodyguards and the kuo-toa in area area 21b. If the characters gather what it needs to complete the statue, Noolgaloop thanks them but decides on a whim to replace the statue’s current head (a rusty lantern) with the head of one of the characters. Noolgaloop fully expects the character to make this sacrifice for the good of the kuo-toa tribe.

God Statue

The archpriest has already given its new god a name: Klaabu. This “god” sprawls on the slimy floor and consists primarily of a decapitated limestone statue depicting a bare-chested male sea elf. Its hands have been replaced with troglodyte claws, and additional limbs have been added in the form of a bugbear’s severed arms. A pair of rusty shortsword blades thrust outward from the statue’s breast, and it wears a kilt of green moss. A rusty lantern serves as the god’s head, inside which rattles a fist-sized green gem—the control gem for the green slaad in area area 4. Any character who casts identify on the gem learns its function.

The figure’s added parts are held in place by the same glue that the kuo-toa apply to their shields.

Monster Carcasses

The kuo-toa have collected more carcasses than the archpriest needs. The rotting collection includes a dead darkmantle wrapped in a net, a bugbear’s severed head and torso, a dead hook horror, and a headless carrion crawler swarming with maggots.

21b. Kuo-toa Carnage

Stench. The air in this cave is fantastically foul.

Kuo-toa. Four poisoned kuo-toa guard this area. Two of them are using spears to cut the head and claws off a dead chuul. The other two are feasting on the corpse of a dead kuo-toa (a former companion).

Troglodyte Corpses. Lying about the cave are the reeking carcasses of five dead troglodytes, one of which has had its claws hacked off.

The kuo-toa are hostile to strangers. If two or more of them are killed or incapacitated, the survivors retreat to area area 21a.

At the start of each turn, any creature not immune to the stench of troglodytes must succeed on a DC 12 Constitution saving throw or be poisoned until the start of its next turn. A gust of wind spell or similar magic can clear the air in the cave for 1 minute, while removing the troglodyte carcasses clears the air for good.

22. Hook Horror Homestead

Cave Features. This cavern has an uneven floor and ceiling, the distance between them varying from 30 to 50 feet. The damp walls are lined with natural shelves and beautiful rock draperies formed by water seepage.

Fungi. Growing out of mounds of bat guano are several towering zurkhwoods, as well as patches of barrelstalk, bluecap, and trillimac.

Noise. Eerie clicking sounds betray the presence of seven Hook Horror.

The opportunistic hook horrors try to hook stray kuo-toa, troglodytes, or adventurers and drag them away to be devoured. Experience has taught them to avoid contact with large, well-armed groups. A party of adventurers moving through the cavern with light sources is enough to keep the hook horrors at bay, as they click and chirp eerily to one another from the shadows.

It’s only a matter of time before the aboleth enslaves the hook horrors or drives them off. The hook horrors have yet to encounter the aboleth and thus don’t realize the danger it represents.

23. Hook Horror Larder

Ambush. A hook horror clings to a 15-foot high ledge, waiting to ambush any who enter. The ledge is set into the western wall, between the two tunnel entrances.

Bones. Lying on the floor are the bones of several troglodytes mingled with the remains of kuo-toa and other unidentifiable humanoids. Characters who search the bones find a lost treasure (see “Treasure” below).

Fungi. Patches of barrelstalk, ripplebark, timmask, and tongue of madness grow near the water that pools against the eastern wall.

Treasure

Amid the bones is a common wondrous item called a pipe of smoke monsters. While smoking this pipe, one can use an action to exhale a puff of smoke that takes the form of a single creature, such as a dragon, a flumph, or a froghemoth. The form must be small enough to fit in a 1-foot cube. It loses its shape after a few seconds, becoming an ordinary puff of smoke.

24. Troglodyte Takeover

Every surface of these caves is coated with slime. Sound travels easily through the caves, though as one moves toward the center of the complex, echoes from the underground river become less obtrusive.

Eighteen troglodytes live in these caves and respond quickly to sounds of battle. These enslaved troglodytes can’t take reactions. When an enslaved troglodyte takes damage, it can make a DC 14 Wisdom saving throw to break free of the aboleth’s control. On a successful save, the troglodyte fights for its own survival, not the aboleth’s. Its first instinct is to flee if it can.

24a. West Sentries

Three enslaved troglodyte guard this 30-foot-high cave. Shattered shields, broken spears, and torn nets (trophies taken from the kuo-toa) lie heaped against the walls. None of this gear is salvageable.

24b. Kuo-toa Bones

This 30-foot-high cave is littered with the bones of four kuo-toa. The bones have all been thoroughly chewed and their marrow sucked out.

24c. General Quarters

Troglodytes. Unless they’ve been drawn elsewhere, twelve enslaved Troglodyte rest atop sawed-off stalagmites in the middle of this 40-foot-high cave.

Pictographs. The walls bear pictographs of kuo-toa abasing themselves before a creature that resembles an otyugh (a bulbous monster with three legs, long tentacles, and a gaping maw).

24d. Abandoned Nursery

The kuo-toa used this 30-foot-high cave as a nursery. The cave has been empty since the kuo-toa were forced to vacate it. Tiny fish bones litter the floor.

24e. East Sentries

The underground river is loudest here. Three enslaved troglodyte guard this 30-foot-high cave.

Aftermath

This level has the potential to be greatly changed by the actions of the characters.

The death of the aboleth allows the surviving kuo-toa to reclaim their grotto (area area 16). The kuo-toa victory is short-lived, however, because the drow start attacking them soon afterward. These attacks continue until the kuo-toa are wiped out or forced to retreat upriver. After taking over the grotto, the drow enslave the troglodytes and use them to farm area areas 3 and area 5. Meanwhile, the drow move the grotto’s treasures to a more secure location, such as the House Auvryndar stronghold on level 10.

If the aboleth survives, it enslaves or kills off the remaining kuo-toa in the coming weeks. The aboleth also enslaves the ettin in area area 2, and its slime poisons and kills off the fungi throughout the Twisted Caverns, destroying the delicate ecosystem. The drow challenge the victorious aboleth but are unable to defeat it on their own, given the limited support they receive from House Auvryndar. Several quaggoths that were once loyal to the drow become the aboleth’s thralls. The resulting stalemate makes the drow desperate for aid, regardless of the source.