Level 11: Troglodyte Warrens

The Troglodyte Warrens are designed for four 11th-level characters, and characters who defeat the monsters on this level should gain enough XP to reach 12th level. These reeking caverns and rough tunnels have long been home to clans of troglodytes. The presence of drow on the levels above and below has turned these warrens into a battlefield—and an opportunity for unlikely alliances.

What Dwells Here?

Troglodytes inhabit this level of Undermountain. Their dominance is contested by drow determined to enslave them, trolls twisted by Halaster’s magic and hungry for troglodyte flesh, and a magically enhanced behir intent on terrorizing all.

Troglodytes

The troglodytes in area area 2 on this level have been captured by drow, and they try to entice adventurers into helping them escape. Meanwhile, the strongest and last remaining free clan of troglodytes defends against encroaching drow in area area 7. The troglodytes might reveal secret locations and treasures to adventurers who eliminate their hated enemies.

Drow

Drow from House Auvryndar on level 10 and House Freth on level 12 are fighting each other for control of this level, all the while capturing troglodytes to use as slaves and doing their best to steer clear of the behir.

Mutated Trolls

The trolls of the warrens have been mutated by the glowing, rune-covered cavern at area area 11. The magic of that cavern has spawned trolls with grotesque deformities and magical traits. These creatures devour troglodytes, drow, and adventurers whenever they can find them. The trolls are smart enough to avoid the behir.

Behir

This serpentine monstrosity feeds on the troglodytes and trolls, keeping their populations in check. Halaster has bestowed the behir with arcane sigils painted on its hide, which it can activate to produce potent magical effects.

The behir roams throughout the level, but characters encounter it for the first time in area area 17. Its presence can be hinted at beforehand, in the form of a flash of blue scales crossing the end of a tunnel. Huge, clawed footprints can be seen marking the ceilings of multiple caverns, and the sound of lightning and thunder erupts from time to time in the distance.

Exploring This Level

All location descriptions for this level are keyed to map 11.

1. Auvryndar Watch Post

Ceiling. The concave ceiling of this cavern rises to a height of 20 feet.

Sentries. A female drow elite warrior named Ventrid Xil’talan leads six drow (two females and four males).

The drow, loyal to House Auvryndar, are tasked with guarding the tunnel that leads up to level 10. They ambush and kill any non-drow coming from that direction.

Treasure

Ventrid wears an obsidian scarab engraved with the insignia of House Auvryndar (25 gp) and a spider-shaped crystal ring set with a black pearl (750 gp).

2. Captured Troglodytes

The cracked bones and skulls of small creatures hunted by the troglodytes litter the tunnels leading to this area, marking the borders of territory that once belonged to their clans. The invading drow from levels 10 and 12 have enslaved the troglodytes that once dwelled here and have traded occupation of this area more than once. The drow of House Auvryndar are currently in control.

2a. Troglodyte Chain Gang

The air in this cavern is heavy with the stench of twenty-two adult Troglodyte. They wear iron shackles on their ankles and are chained together while awaiting relocation to Muiral’s Gauntlet (level 10).

A shackled troglodyte’s speed is halved, and it can’t move more than 5 feet away from the other troglodytes it is chained to. The drow mage in area area 2c has the keys to the shackles. A character can pick the lock on a set of shackles with a successful DC 15 Dexterity check using thieves' tools.

Even if they are freed, the troglodytes won’t flee this area while the drow are holding their young (see area area 2c). Although initially fearful, the troglodytes engage with the characters in an attempt to turn them against the drow. They promise treasure in exchange for freeing them and their young. Characters who don’t speak Troglodyte and don’t have access to a tongues spell or similar magic can use gestures, pictures, or other crude methods to communicate with the troglodytes on a rudimentary level. Getting a message across in this way requires a successful DC 15 Charisma (Performance) check.

If the characters show no interest in aiding them, the troglodytes begin to bow down and chant loudly, as if worshiping the characters. They try to catch the attention of the drow in area area 2c, hoping this display will anger the drow and prompt them to attack the characters.

The troglodytes enter any fight against the drow, under the limitations of their shackles. If they can, they focus their attacks on Tsabdrar Do’ett (see area area 2c), hoping to acquire the key to the shackles. Any freed troglodyte tears into the drow with a vengeance.

If the characters help to liberate the troglodytes and their young from the drow, the troglodytes show the characters the secret door that leads to area area 2d and allow them to take the treasure that’s there. If the characters are unintentional participants in the troglodytes' escape, the troglodytes offer up the treasure only if they are subsequently threatened.

2b. Arch Gate to Level 6

A stone arch is embedded in the west wall of this 10-foot-high cave, just around the corner from the entrance tunnel. The arch is one of Halaster’s gates (see “area Gates"). Carved into the arch’s keystone is a hand-shaped indentation with a sigil representing magic scribed into the palm. Its rules are as follows:

• Casting the mage hand cantrip and pressing its spectral fingers into the keystone’s indentation opens the gate for 1 minute.
• 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 40 on level 6, in the closest unoccupied space next to the identical gate located there.

2c. Amoral Dilemma

Monsters. At the north end of the cave, five male Drow Elite Warrior are holding eleven troglodyte young (Small noncombatants) at sword point. A male drow mage named Tsabdrar Do’ett is contemplating what to do with the troglodyte young.

Crates. Zurkhwood crates half filled with iron chains and shackles stand in the south end of the cave.

Secret Door. A seam in the rock wall reveals a secret swivel door covered with oily troglodyte secretions. Anything that touches the oily door carries the mildly revolting stench of troglodytes for 1 hour or until the item is washed. The stench is not as potent as a troglodyte’s Stench trait and imposes no conditions on those who catch a whiff of it.

The drow mage is deciding whether to kill the troglodyte young, because they are too small to be shackled. His inclination is to do so, and only the characters' interference stays his hand. Tsabdrar carries keys that unlock the shackles stored in this room as well as the shackles on the troglodytes in area area 2a.

The drow investigate any commotion in area area 2a and attack intruders who appear to be aiding or influencing the troglodytes. If the characters aren’t doing so (or if they are able to negotiate an end to any initial hostilities), the drow are willing to bargain with them. They explain that a behir has been rampaging through this level, killing all the creatures it encounters. If the characters defeat the behir—and eliminate any drow of House Freth they encounter along the way—Tsabdrar promises that House Auvryndar will let them keep the behir’s hoard. He also promises to spare the troglodyte children. A successful DC 15 Wisdom (Insight) check confirms that both assurances are false.

Treasure

Each drow wears an obsidian scarab engraved with the insignia of House Auvryndar (25 gp). Tsabdrar also carries a thin, leather-bound spellbook containing the spells he has prepared.

2d. Troglodytes' Trove

This cave features natural shelves lined with the skulls of the troglodytes' former leaders.

Treasure

Piled on the floor in plain view is the troglodytes' wealth: 920 gp, a silvered longsword, and three amethyst orbs (750 gp each).

3. Hungry Gnome

Corpses. Eight drow corpses are splayed like rag dolls across the floor of this 10-foot-high cavern.

Troll in Gnome Form. A naked, hairless, gray-skinned deep gnome is gnawing on one of the corpses. (The gnome is really a troll named Xlorp, transformed by the runes in area area 11b.)

In its current form, the troll has the statistics of an unarmored (AC 12), chaotic evil deep gnome (svirfneblin) that speaks only Giant. Casting a successful dispel magic spell (DC 19) on the troll causes it to revert to its normal form. Xlorp also reverts to its normal form when its gnome form is reduced to 0 hit points. It has full hit points in its troll form, but any excess damage from the attack that caused it to revert is carried over to that form.

Xlorp follows the characters around if they give it food. It fights alongside the party, as long as it remains happy and fed. If Xlorp is mistreated in any way, it goes berserk and attacks everyone.

The drow were killed by the behir. A character who examines the bodies and succeeds on a DC 10 Wisdom (Medicine) check reveals that four drow are covered in burn marks consistent with lightning strikes, three were torn to pieces by large claws, and one was crushed to death (a victim of the behir’s coils).

4. Loathsome Limbs

Rock Formations. Stalactites and stalagmites fill this area.

Warty Limbs. Six severed troll limbs (five arms and one leg) and a decapitated troll head lie in pools of dark, sticky blood across the floor.

Bloody Trail. A trail of large, bloody claw marks meanders around the stalactites on the ceiling, then exits to the southwest.

When the characters pass through this area, the limbs twitch as they come to life and attack, as described in the “Variant: Loathsome Limbs” sidebar in the “Troll” entry in the Monster Manual. Any character who succeeds on a DC 10 Wisdom (Medicine) check can identify the body parts as belonging to three separate trolls, which were torn apart and partially devoured by the behir. The tracks on the ceiling belong to the behir and fade out halfway to area area 14.

5. Trolling the Troglodytes

Ceiling. This ceiling varies in height from 15 to 30 feet.

Battle. A five-armed troll is engaged in battle with six Troglodyte in the northwest part of the cave.

Pit. The southwest edge of the cave borders a 30-foot-deep, yawning pit with nothing in it.

Secret Door. The north wall contains a secret door that swivels on a central axis. The secret door can be seen automatically from inside the tunnel.

If the characters watch to see how the battle plays out between the troglodytes and the troll, assume that one troglodyte dies each round, while the troll’s hit points do not decrease thanks to its Regeneration trait. If the characters come to the troglodytes' aid, the fearful troglodytes disengage from combat on their next turn, flee through the secret door, and retreat to area area 7a, leaving the characters to deal with the troll on their own.

The mutated troll has an extra pair of arms sprouting from its chest and a fifth arm growing out of its back. The troll has made a successful saving throw against the stench of the troglodytes. It has the statistics of a normal troll, with these changes:

• It has 44 hit points when the characters first arrive.
• It makes an additional three claw attacks as part of its Multiattack action.

In its wounded state, the troll has a challenge rating of 6 (2,300 XP). If it regains all its hit points, its challenge rating becomes 8 (3,900 XP).

6. Piercer Cavern

This cavern is filled with stalactites and stalagmites, and hidden among the stalactites are twenty-six Piercer. A piercer drops onto any creature that ends its turn in the cave, until all the piercers have dropped.

North of the cavern is a 30-foot-deep, yawning pit with nothing in it. Beyond this pit lies area area 5.

7. Troglodyte Lair

The last free clan of troglodytes inhabits these caves. Its members live in equal fear of the behir, the trolls, and the drow. Adventurers are perceived as just another threat until they prove otherwise. Characters who don’t speak Troglodyte and don’t have access to a tongues spell or similar magic can use gestures, pictures, or other crude methods to communicate with the troglodytes on a rudimentary level. Getting a message across in this way requires a successful DC 15 Charisma (Performance) check.

7a. Battle-Ready Troglodytes

Ceiling. Stalactites dot the ceiling, which runs from 30 feet high in the north to 50 feet high in the south.

Floor. This cavern has a muddy, uneven floor.

Troglodytes. Eighteen adult Troglodyte take cover behind a scattering of stalagmites. (Add to this number any troglodytes that fled from area area 5 or escaped from area area 2.)

Ledge. A stone slope along the east side of the cave rises up to a long ledge toward the south. The ledge is 20 feet above the cavern floor and has four tunnels opening off it. A fiery glow spills out of the tunnel that leads to area area 7d (see that area for details).

Secret Door. A secret door at the southwest corner of the cave swivels on a central axis. The secret door can be seen automatically from inside the tunnel.

The troglodytes are bracing for another drow attack from the north. The clan’s current leader is a troglodyte with 20 hit points named Kol’daan. He carries a wooden sparring sword and can replace each of his claw attacks with a sword attack, dealing 4 (1d4 + 2) bludgeoning damage on a hit. Whether in battle or negotiations, Kol’daan is prone to striking heroic poses with his sparring sword and giving inspiring speeches in Troglodyte.

7b. Battleground

The floor of this damp cavern is littered with the corpses of twenty-one troglodytes and nine drow, all surrounded by pools of sticky blood and in different stages of decay (suggesting that more than one battle occurred here). The troglodytes were felled by drow weapons, while the drow were torn to pieces by the troglodytes' teeth and claws. Some of the drow corpses are half eaten.

7c. Wounded Troglodytes

Four adult Troglodyte occupy this side cave. One troglodyte is at full health and guards the other three, which are wounded (each has 1d6 hit points remaining). If the characters offer magical healing to all the wounded troglodytes and word of the deed gets around, they gain advantage on subsequent Charisma checks made to influence any troglodytes throughout area area 7.

7d. Fire Beetle Farm

A fiery glow emanates from this cavern. Six Giant Fire Beetle live here, watched over by a troglodyte with a 10-foot pole. Since being trapped by the drow, the troglodyte clan has taken to raising the beetles for food.

7e. Halaster Formation

Centuries of dripping sediment have created a rock formation on the back wall of this cavern that resembles the face of Halaster Blackcloak. The troglodytes have left small offerings around the formation, including a half dozen balls of bat guano, a garland of drow intestines, and a muddy dagger with a curved blade.

Treasure

The muddy dagger is a dagger of venom. The troglodytes are unaware of its magical nature.

7f. Troglodyte Nursery

Four adult Troglodyte look after twenty-two troglodyte young (Small noncombatants) in this area. Two of the adults stand guard in the front cave; the other two feed and play with the young troglodytes in the rear cave.

7g. Chieftain’s Cave

The last troglodyte chieftain was killed by drow some time ago, leaving Kol’daan in charge. Lurking in the chieftain’s cave are three toothless old Troglodyte, each with 8 hit points remaining and no bite attack. These evil troglodytes served as the former chieftain’s advisors. Kol’daan thinks they’re weak and wants nothing to do with them. They fight only in self-defense, and each has a challenge rating of 1/8 (25 XP).

Secret Door

A secret door stands in the northwest wall of this cavern. The old troglodytes won’t divulge the secret door’s location, and they spit insults at anyone who dares to open it.

7h. Blessed Laogzed

This dank cave contains a 5-foot-tall, 8-foot-diameter mud sculpture of a loathsome creature that combines the features of a demonic toad and a lizard. Any character who has an appropriate background or who succeeds on a DC 15 Intelligence (Religion) check knows that the sculpture represents the demon-god Laogzed, worshiped by many troglodytes.

Treasure

Smashing open the mud sculpture of Laogzed reveals fifty malachite gemstones (10 gp each).

8. Illusory Front Line

The drow of House Freth have learned the hard way that the troglodytes in area area 7 are too hardy and stubborn to be easily conquered. A male drow mage named Orl Telenna has been tasked with holding these caves until reinforcements arrive. Using the resources at his disposal, Orl has created illusions designed to discourage the troglodytes from entering this area. As part of this tactic, he has the hallucinatory terrain spell prepared instead of Evard’s black tentacles, seeming instead of cloudkill, and rope trick instead of alter self.

8a. False Impasse

Thanks to Orl’s hallucinatory terrain spell, this 20-foot-high cavern appears to be filled from wall to wall with a pool of bubbling acid. The caustic scent of the acid seems real to any creature that approaches this area, but contact with the acid deals no damage. The illusion can be removed with a successful dispel magic spell (DC 14). Orl refreshes the spell each day.

8b. False Camp

Orl has created a false camp inside a 30-foot-square area in the middle of this rubble-strewn cavern. The camp appears to be a quiet gathering of nine well-armed drow wizards and warriors, who are communicating with one another using sign language. In truth, the drow are nine troglodyte Zombie created using animate dead and disguised with a seeming spell.

8c. Orl’s Cave

Water. Fresh water trickles into this cave from cracks in the dead-end tunnels to the west, forming a 5-foot-deep pool over much of the floor.

Encampment. A rough camp is set up in an alcove to the southeast.

The alcove holds a blanket, a cask of mushroom wine, and a satchel made of spider silk that contains 10 days of rations and Orl’s spellbook (see “Treasure” below). Orl spends most of his time here, but he listens for trouble and slips out every once in a while to check area area 8b.

Orl’s orders don’t include fighting troglodytes or well-armed adventurers singlehandedly. If he discovers any creatures approaching, he casts a rope trick spell, climbs into the extradimensional space created by the spell, and pulls up the rope. He hides this way for 10 minutes before poking his head out to see if the intruders have left. If he doesn’t have time to hide in this manner, he casts a greater invisibility spell on himself and retreats to area area 9b.

Treasure

Orl’s spellbook contains a drow mage’s normal spells, plus animate dead, hallucinatory terrain, rope trick, and seeming.

9. Contested Caves

The drow of House Freth maintain a tenuous hold over these caves. Their defenses are tested daily by troglodytes, trolls, and infiltrators loyal to House Auvryndar.

9a. Hidden Threats

Sentries. Two male Drow Elite Warrior are hidden behind a natural column of rock to the north.

Eater of Corpses. The cave is full of rotting corpses (twenty troglodytes, nine drow, and five giant spiders). At the midpoint of the cavern, a fat troll rendered permanently invisible by Halaster’s magic is feasting on one of the spider corpses.

The drow, Eilthymmar and Zaztorrl, serve House Freth. They have been watching the invisible troll but aren’t sure what to make of it. They retreat to area area 12 (through area areas 9b, area 10a, and area 10b) if threatened.

Zaztorrl’s loyalty to House Freth is shaky, the result of a series of dull assignments that have left him feeling underappreciated and scornful. If the characters capture or corner him, he offers to lead them to House Freth’s fortress on level 12 in exchange for his freedom. If he is treated with respect, Zaztorrl might befriend the characters and help them in battle.

A successful dispel magic spell (DC 18) cast on the troll renders it visible for 1 minute. The troll attacks any creature it sees, but retreats to area area 10a (through area area 9d) the first time it takes acid or fire damage.

9b. Drow Staging Area

This 20-foot-high cavern is used as a staging area for House Freth’s raids into troglodyte territory. Six drow loyal to House Freth (four females and two males) and four Shadow Demon lurk here. The drow and their demon allies are planning to soften up the troglodytes in area area 7a and are not expecting to face adventurers. If four of the drow fall, the survivors use darkness spells to cover their retreat to area area 13.

9c. Roper Ruse

The drow and the troglodytes avoid this cave because they think a roper lives here—but the creature is an illusion created by Halaster.

Characters who can see into this dark cave observe that the northernmost stalagmite has a single glaring eye, a fang-filled mouth, and six waving tendrils. A detect magic spell reveals an aura of illusion magic around the stalagmite, and a successful DC 15 Intelligence (Investigation) check confirms that the “roper” is a silent illusion cast on an otherwise ordinary stalagmite. A successful dispel magic spell (DC 15) cast on the stalagmite ends the illusion, which doesn’t attack or react to anything. Any attack or effect that targets the roper ends up targeting the stalagmite instead. The stalagmite has AC 17, 120 hit points, and immunity to poison and psychic damage. A character who sees the roper take damage can repeat the Intelligence (Investigation) check to discern that it’s an illusion.

9d. Stalagmites

This 20-foot-high cavern contains a forest of stalagmites and nothing else.

10. Troll Tunnels

The drow patrol these areas frequently, always on the lookout for the trolls that lurk here.

10a. Sinkhole

This 30-foot-high cave is filled with the echoes of water dripping from stalactites, as well as the fluttering wings of thirteen Stirge that live in a 30-foot-deep sinkhole to the west. The stirges attack anyone that disturbs them.

10b. Main Artery

A mutated troll} feeds on a dismembered drow corpse in this 10-foot-high passage. The troll is a corpulent specimen covered with green boils. Whenever it takes damage, roll a d6. On a 5 or 6, one of the troll’s boils bursts open, releasing a {@creature swarm of insects (wasps) that fills a random space within 5 feet of the troll. The swarm acts on its own initiative count and attacks the nearest creature that isn’t a troll. If the troll is killed, it no longer releases any swarms.

11. Forest of Stone

These 20-foot-high caverns are filled with stalagmites, stalactites, and other rock formations, giving this area the appearance of a dense forest of stone.

11a. Standing Gate to Level 8

Among the rock formations is a standing gate (see “area Gates") formed by a pair of 10-foot-tall stalagmites carved to create the image of giant stone snakes wrapped around them. The points of the stalagmites have been sawed off, and a lintel stone rests atop them. Chiseled into the lintel stone are the words “DON THE CRYSTAL CROWN” in Dwarvish. The rules of this gate are as follows:

• The gate opens for 1 minute if a creature wears King Melair’s crystal crown (area level 6, area 11d) while standing within 5 feet of it.
• Characters must be 10th 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 18b on level 8, in the closest unoccupied space next to the gate located there.

11b. Trollwarp Cavern

Stalagmites. This 20-foot-high cave contains ten stalagmites that been twisted by Halaster’s magic so that each bears a passing resemblance to the Mad Mage: an old wizard in a robe covered with lidless eyes, his visage frozen in a mad scream.

Glowing Runes. Floating above each stalagmite is a glowing rune.

A character who succeeds on a DC 15 Intelligence (Arcana) check recognizes that the runes floating above the stalagmites represent the school of transmutation. A detect magic spell reveals an aura of transmutation magic around each stalagmite. The runes' magic poses no danger to adventurers, but it causes weird, permanent transformations in any troll that lingers in this area. (For example, a troll might sprout an extra head or tentacles, or gain some kind of magical ability or aura.) Casting dispel magic on a rune causes it to vanish—and makes the stalagmite below it explode. Each creature within 20 feet of an exploding stalagmite must make a DC 15 Dexterity saving throw, taking 22 (4d10) bludgeoning damage on a failed save, or half as much damage on a successful one.

If the characters linger here, a magical gate might open just long enough to expel 1d4 + 2 Troll and an equal number of chickens. The trolls immediately chase the chickens—or any other visible food source.

12. Drow Battle

Characters who approach this 50-foot-high cavern for the first time hear the sounds of battle ahead.

Demons. In the narrower section between the north and south halves of the cavern, two Chasme fight a hezrou. All three demons are glowing.

Drow. Two opposing groups of drow are peppering one another with spells and crossbow bolts, ignoring the demons. Ten drow spread out north of the demons. Sixteen drow stand south of the demons.

Corpses. The bodies of fifty drow and twenty troglodytes litter the battlefield amid pools of demon ichor. Their gear is unsalvageable.

The cavern is the site of a heated battle between House Freth (to the north) and House Auvryndar (to the south). House Freth’s forces are nine male drow led by a male drow mage named Spirreth Dalambra. The forces of House Auvryndar are fifteen drow (twelve females and three males) led by a female drow priestess of Lolth named Shindreer Argonrae.

The chasmes are agents of House Freth, while the hezrou is a servant of House Auvryndar. All three demons are outlined with faerie fire spells cast on them by drow of the opposing side.

Characters who side with one drow house become the focus of the opposing house’s wrath. If the characters side with the house that wins, the leader of the victorious drow parleys with them to find out what they expect in return (see below). If the characters end up on the losing side, the drow show them no mercy.

If the characters stay out of the fight, the forces on both sides dwindle slowly until the hezrou finally defeats the chasmes. The drow mage, Spirreth, escapes using greater invisibility, leaving his forces to die fighting the hezrou. He has expended all his spell slots and must drink a potion (see “Treasure” below) to restore his lost hit points. If he escapes, Spirreth tries to hide and rest in area area 13. The hezrou has 72 hit points remaining at the end of the fight, and Shindreer has cast none of her spells. She uses her healing magic to return the demon to full health as quickly as possible. House Auvryndar’s surviving fighting force consists of six female drow, which are healed by Shindreer’s mass cure wounds spell.

Spirreth Dalambra

Spirreth found himself forced to assume command of House Freth’s dwindling forces on this level after his superior, Beranica Freth, was killed by demons. Spirreth’s job was to protect and serve Beranica. Now he faces the unwelcome task of reporting her death to her older sister, Erelal Freth, on level 12.

If the characters help Spirreth overcome the forces of House Auvryndar, or if they corner and capture him, he slyly offers to facilitate an audience with Erelal Freth, commander of the House Freth fortress on level 12. Spirreth declares that Erelal will want to reward them for their heroism or trade for his safe release. But the drow mage’s offer is merely a desperate ploy to please his superiors, which characters can ascertain with a successful Wisdom (Insight) check contested by his Charisma (Deception) check. Spirreth is actually hoping to deliver the characters to Erelal Freth, then pass them off as Beranica’s murderers.

Treasure

Spirreth’s spellbook contains all the spells he has prepared, plus crown of madness, fear, Melf’s acid arrow, and sending. Fastened to his cloak is an obsidian scarab engraved with the insignia of House Freth (25 gp). In a special pouch on his belt, he carries a potion of supreme healing in a clear crystal vial (5 gp).

Shindreer Argonrae

Shindreer is a powerful member of her small drow house, and she has pledged its strength to the larger cause of House Auvryndar. She also considers Vlonwelv Auvryndar her mortal enemy, however, and has plans to depose her—thus reversing the relationship of fealty between Houses Auvryndar and Argonrae.

Fully aware of her rival’s ambitions, Vlonwelv ordered Shindreer to the front lines in the mounting conflict against House Freth. Vlonwelv was counting on House Freth to take care of Shindreer for her, but Shindreer has proven harder to kill than Vlonwelv anticipated.

If the characters killed Vlonwelv on level 10 and they share this information with Shindreer, she becomes enraged that they deprived her of that pleasure and attacks them.

Treasure

Shindreer wears spider silk gloves with bloodstones sewn into them (750 gp for the pair) and a silver holy symbol of Lolth (25 gp). Worked into the handle of her scourge is an obsidian scarab engraved with the insignia of House Argonrae (25 gp).

13. Freth Refuge

Thick web curtains are strung between the stalactites and stalagmites that fill this 30-foot-high cavern. Unless they are cut down or burned away, the webs create a veritable maze, reducing visibility in the cavern to 10 feet. They also catch bats, lizards, and stirges, many of which are still alive and squawking.

At the north end of the cavern, hidden behind a stalagmite, is a cache of supplies left here by drow scouts of House Freth. The supplies include a cask of mushroom wine, 20 days of rations (dry meat and moss) in a satchel made of lizard skin, and a sealed gourd containing 20 applications of drow poison (see “Poisons” in chapter 8 of the Dungeon Master’s Guide).

14. Auvryndar Watch Post

Ceiling. The ceiling and floor in this area are uneven, the distance between them ranging from 20 to 40 feet. Three natural columns of rock support the roof.

Scouts. Two female Drow Elite Warrior (named Akora and Danafay) are mounted on Giant Lizard near the center of the cavern.

The drow attack at the first sign of intruders. Their lizards are fitted with saddles, reins, and stirrups, and have the Spider Climb trait (see the “Variant: Giant Lizard Traits” sidebar in appendix A of the Monster Manual). The drow take the lizards up the walls so they can get a better look at the characters as they approach.

If the characters veer toward area area 12 from here, Akora and Danafay try to get there first to warn Shindreer.

Treasure

Each drow wears an obsidian scarab engraved with the insignia of House Auvryndar (25 gp).

15. Cleared-Out Caves

Troglodytes once lived here, but most of them were captured by drow or devoured by the behir and the trolls.

15a. Filthy Den

Once a troglodyte den, this 20-foot-high cave is strewn with filth. Foul, oily secretions on the walls were left there by the troglodytes.

15b. Stone Troll

A mutated troll is searching through piles of troglodyte filth for edibles. The troll looks normal but has a peculiar trait. At the start of each of its turns, roll a d6. On a 1, the troll turns to stone and is petrified until the start of its next turn. Casting a greater restoration spell on the troll rids it of this magical malady.

15c. Empty Nursery

The troglodytes once raised their young here, and the floor is strewn with the bones of vermin.

16. Arch Gate to Level 7

Embedded in the north wall of this 10-foot-high cave is a stone arch. Carved into its keystone is a picture of a hand clutching a lit torch. The arch is one of Halaster’s magic gates (see “area Gates"). Its rules are as follows:

• If a lit torch is brought within 5 feet of the arch, the gate opens for 1 minute.
• 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 29 on level 7, in the closest unoccupied space next to the identical gate located there.

17. Behir Lair

The floor of the behir’s musty lair is covered with broken bones that crunch underfoot. Creatures that walk on the floor have disadvantage on Dexterity (Stealth) checks made to move silently through these caves.

17a. The Maw

Rock Formations. Sharp-pointed stalagmites and stalactites fill this 40-foot-high cave, giving it the appearance of a toothy maw. Harmless bats flutter between the stalactites.

Lightning Flashes. If the behir is in area area 17c, sporadic flashes of blue-white light appear in the tunnel leading to that area, accompanied by a crackling noise.

17b. Crushed Drow

The half-eaten corpse of a recently slain male drow leans against the stalagmite at the northern entrance to this 30-foot-high cave. The drow’s chest is caved in where the behir stepped on it.

17c. Behir

The behir lies in wait in this 50-foot-high cavern, its muscled, serpentine body woven through the stalagmites. Scars are carved into its hide in the form of arcane runes, placed there by Halaster. The runes grant the behir the ability to use the following legendary actions.

Legendary Actions

The behir can take three legendary actions, choosing from the options below. It can take only one legendary action at a time and only at the end of another creature’s turn. The behir regains spent legendary actions at the start of its turn. Its spellcasting ability is Charisma (spell save DC 13).

Lesser Magic. The behir casts color spray or sleep, requiring no components.

Greater Magic (Costs 2 Actions). The behir casts invisibility or misty step, requiring no components.

17d. Hoard of the Behir

This ledge stands 30 feet above the floor of area area 17c and 20 feet below the cavern roof. The behir has fashioned a nest of bones here, decorated with gleaming coins and gems.

Treasure

The behir’s hoard includes 6,700 gp, 4,100 sp, a gold-and-onyx scorpion brooch (250 gp), a silver music box of elven design (1,000 gp), and a dread helm. A common wondrous item, the dread helm is a fearsome steel helm that makes its wearer’s eyes glow red.

Aftermath

Houses Auvryndar and Freth continue to send forces to this level until their strongholds (on levels 10 and 12, respectively) are destroyed. In addition to drow, adventurers could find themselves facing demons sent by the drow to destroy the behir. Drow that succeed in killing the behir take its treasure back to their stronghold.

If the characters eliminate the behir, neutralize the trolls, and deal crippling blows to House Freth and House Auvryndar on this level, the troglodytes grow in strength and numbers. Even if the troglodytes are also eliminated, new clans journey here from elsewhere in Undermountain. Emboldened by their lack of enemies, troglodytes that regain control of their former warrens turn hostile toward all other creatures, regardless of any past truces.