Waterdeep: Dungeon of the Mad Mage

Hobgoblin Patrols

Hobgoblins of Doomcrown's phalanx have secured most of the halls and chambers in Arcturiadoom. Consequently, the only wandering monsters of consequence are hobgoblin patrols. A typical patrol consists of four hobgoblins. Their marching footsteps and clanking armor can be heard well in advance of their arrival, and characters can't be surprised by them. Combat with a patrol is sure to alert other creatures in the vicinity.

If any hobgoblins are defeated while on patrol, subtract their numbers from the guards in x.

1a. Worm Tunnel

The bore worm on level 13 wanders down here occasionally, looping around a central column of rock before traveling back up. This column supports the cavern's 30-foot-high roof. The cavern also has these features:

The two drow mages are males named Hulziin and Yrrprek. Each wears a cloak pin bearing the insignia of House Freth. They arrived here shortly before the adventurers and have greater invisibility spells cast on them. The drow and their two quasit companions try to remain hidden, allowing adventurers to move into Arcturiadoom ahead of them. Once the path is clear, they pass through x and 76b on their way to x.

One of their kin, Vanar, arrived early to scout and has already slipped inside. The characters might encounter him and his shadow demon in x.

1b. Stalactites and Stalagmites

This damp, dripping cave contains a veritable forest of stalagmites and stalactites.

1c. Claw-Shaped Cave

The drow have hidden supplies in the deepest arm of this otherwise empty cave. A search reveals three backpacks made of woven spiderwebs. Each pack contains a mess kit, 10 days of rations (dried mushrooms, moss, and boiled cockatrice eggs), 50 feet of spider silk rope, and a full water skin made from a lizard's bladder.

2a. Deformed Duergar

Characters who enter this cave are soon attacked by a hideously deformed duergar. The creature has enlarged itself to a height of 9 feet.

This creature used to be two separate duergar, a male named Blork and a female named Muatha. Arcturia fused them together into a single creature by using magic that only a wish spell can undo. Both skulls merged into one bulbous head that has three ears, three eyes, two noses, and two mouths. It has a third arm on the right side of its body, and its left leg splits into two at the knee, giving it three feet. The transformation drove the poor creature insane, and it regards all other creatures as threats that must be destroyed.

The creature is a duergar, with these changes:

• The creature has 40 hit points.
• It has advantage on Wisdom (Perception) checks and on saving throws against being charmed, frightened, stunned, or knocked unconscious.
• As a bonus action, it can make an attack with its javelin.

2b. Duergar's Crib

The deformed creature in x sleeps here on a bed of spongy black mold that grows at the back of the cave.

2c. Fungus Gardens

The creature in x comes here to feed, as do other creatures dwelling in the caverns. The cave has the following features:

The crawlers are natural enemies of the creature in x, which recently killed one of them with a blow from its war pick. They ignore characters who keep a respectful distance.

A character who studies the fungus and succeeds on a DC 10 Intelligence (Nature) check can distinguish edible varieties from poisonous ones, and also ascertains that the spore clouds are harmless. A character unaware of this information who eats fungus has a 50 chance of consuming a poisonous variety and must succeed on a DC 10 Constitution saving throw or be poisoned for 1d4 hours.

2d. Standing Gate to Level 12

This cave contains a pair of standing stones with an inanimate minotaur skeleton embedded in each one, facing each other. These standing stones form one of Halaster's magic gates (see "x"). The rules of the gate are as follows:

• Any creature that touches one of the standing stones is targeted by a maze spell (save DC 22).
• To open the gate, a creature must escape the labyrinth created by the maze spell. When it returns, the gate opens for 1 minute.
• Characters must be 12th level or higher to pass through this gate (see "x"). The first creature to pass through the gate triggers an elder rune (see "x").
• A creature that passes through the gate appears in x, in the closest unoccupied space next to the identical gate located there.

5a. Domed Chamber

This room has a domed ceiling 20 feet high. It is otherwise empty.

5b. Teleport Destination

This chamber has a flat ceiling 15 feet high. Creatures teleported from x arrive here. The room is otherwise empty.

Mithral Keys

A character who inspects the statue and succeeds on a DC 15 Wisdom (Perception) check discovers that one of the eyes carved into Halaster's robe is a button. Pressing this button causes two keys tucked under Halaster's robes to clatter onto the floor around the statue's base. Each key is a flat, 6-inch-long piece of mithral worked into a curious shape.

The first key is shaped like an F, the second like a V with a small loop at the bottom. These are two of the six keys required to activate the weapon of mass disintegration in x.

9a. Training Room

Characters who listen at the door hear guttural cheers coming from within. The room contains six hobgoblins. Two are engaged in mock swordplay with dulled blades in the middle of the room while the other four cheer them on. The room is otherwise empty.

9b. Crypt

A granite sarcophagus against the north wall has been opened, its lid dumped onto the floor. Dust and cobwebs cling to its sides, obscuring ancient inscriptions.

The sarcophagus contains the dusty remains of a Melairkyn dwarf entombed here thousands of years ago. The inscriptions on the sarcophagus, written in Dwarvish, translate as follows: "Thou hast found the final resting place of Harlsnod Darkshine—architect, trap builder, and drinker of fine ales."

9c. Hobgoblin Phalanx

Here, a hobgoblin captain has marshaled a phalanx of twenty hobgoblins. The captain faces east and recites a liturgy in Goblin to the dread god Maglubiyet while the soldiers stand at attention in two rows of ten, facing west. As she reaches dramatic peaks in the liturgy, the hobgoblins grunt and nod approvingly, banging their fists on their armor.

The hobgoblins attack intruders on sight. A battle here pulls reinforcements from x, 733, and 737. It also attracts the attention of the fire giant metalsmith in x.

Statues and Mithral Key

The north statue depicts a smiling female dwarf raising a stone tankard. Hidden in the tankard is a flat, 6-inch-long mithral key shaped like an H missing its top left stem. This key is one of six required to activate the weapon of mass disintegration in x.

The south statue depicts a headless male dwarf resting a large pair of stone tongs on one shoulder; its head cracked when it hit the floor, and it falls apart into two halves if disturbed.

12a. Hell Hounds

The pits are 70 feet deep but partially filled with scrap metal that reduces their effective depth. The western pit is 20 feet deep, the central pit is 50 feet deep, and the eastern pit is 10 feet deep. Any creature that falls into the pit lands on jagged shards of metal and takes slashing damage instead of bludgeoning damage from the fall.

12b–12d. Elemental Forges

These three identical chambers have stone stairs that climb 10 feet to each platform, at the back of which is a raging hot forge of blackened stone. The curved ceilings in these chambers are 20 feet high.

Three fire giants (two females named Dralkana and Ingritt and a male named Yarshoss) are stationed here, one at each forge. Their job is to melt down fragments of scrap iron so that Hrossk, the fire giant metalsmith in x, can reshape them for the construct in x. It's tedious work, and the fire giants are restless and spoiling for a fight.

The fires in the forges are conjured from the Elemental Plane of Fire. A stone lever built into each forge closes a valve in the back of it, extinguishing the flames. Any creature that enters a lit forge or starts its turn in one takes 55 (10d10) fire damage.

13a. Woven Eyes

All three pillars and their silver knobs radiate auras of transmutation magic under the scrutiny of a detect magic spell. Any creature that touches a pillar's silver knob is teleported to x. Once a silver knob has teleported a creature, it disappears. Eight hours after the last knob vanishes, all three reappear.

13b. Alteration Chamber

The buttons on each brass panel and their effects are as follows:

The top button is engraved with an arrow pointing up. Pressing it opens the crystal door, which retracts into the ceiling. This button is locked and cannot be pressed if the door is already up.

The bottom button is engraved with an arrow pointing down. Pressing it shuts the crystal door by lowering it back into place. This button is locked and cannot be pressed if the door is already down.

The left button is engraved with a tiny human stick figure. The button is locked and cannot be pressed while the crystal door is open. If the button is pressed while the door is closed, the light emanating from the crystal dome on the ceiling flickers, and all creatures in the chamber behind the door magically shrink as though affected by the reduce effect of the enlarge/reduce spell (no saving throw allowed). The effect lasts for 24 hours.

The right button is engraved with a larger human stick figure and functions like the left button, except the creatures in the alteration chamber are enlarged instead of reduced.

If a magically reduced creature is subjected to the chamber's enlarge effect, or a magically enlarged creature is subjected to the reduce effect, the two alterations cancel each other out, and the creature reverts to normal size. The effects of the chamber aren't cumulative—a reduced creature that is reduced again or an enlarged creature that is enlarged again doesn't change size further.

Each time the alteration chamber's reduce effect or enlarge effect is activated, roll a d6. On a 1, the chamber malfunctions. Instead of the normal effect, all creatures inside the chamber must make a DC 20 Constitution saving throw, taking 44 (8d10) force damage on a failed save, or half as much damage on a successful one. You can replace this damaging effect with a more benign one. For example, the chamber's magic might cause creatures' noses to elongate or turn their skin blue; an alteration of this sort can be undone with a greater restoration spell or similar magic.

Pit and Sarcophagus

A character needs climbing gear or magic to scale the walls of the pit, which are made of smooth stone.

The sarcophagus at the bottom of the pit has a bas-relief of a laughing dwarf carved into its lid, the rim of which bears the following inscription in Dwarvish: "Here lies Lulz Klangphorn, trapsmith. He is survived by his work." The lid can be pushed aside with a singular or combined Strength of 18. The sarcophagus contains nothing but dust, bones, and Lulz's bronzed skull.

Removing Lulz's skull from the sarcophagus causes mechanisms in the surrounding walls to grind and clank loudly, as though a complex trap has been set in motion. The effect, though harmless, is meant to frighten tomb robbers. After 1 minute, the noise stops.

19a. Spell Component Storage

The stove was given a semblance of life through an animate objects spell made permanent by a wish spell. It tears free of its stovepipe and charges forward on clawed feet to attack intruders.

The stove is a Large construct with a challenge rating of 3 (700 XP). It has AC 17, 50 hit points, a walking speed of 30 feet, and the following ability scores: Strength 14, Dexterity 10, Constitution 10, Intelligence 3, Wisdom 3, and Charisma 1. It has blindsight out to a range of 30 feet and is blind beyond this distance. It has the following action options:

19b. Inanimate Objects

Scattered about this room are inanimate objects that Arcturia animates using the animate objects spell:

• A brass brazier set atop a 3-foot-high tripod and a wooden broom (Small objects)
• A wooden coat rack; an iron torture chair festooned with spikes; a 10-foot-long, 250-pound chain; and a fat iron cauldron (Medium objects)
• A stone mine cart and a life-size, hollow bronze statue of a bull (Large objects)

23a. Shoe Hulk

Lying in the middle of this room is an old shoe with a scorpion hiding in it. If the shoe is disturbed, the scorpion scuttles out and attacks the nearest creature.

The scorpion is, in fact, an umber hulk under the effect of a polymorph spell made permanent with a wish spell. The umber hulk reverts to its true form and attacks when its scorpion form is reduced to 0 hit points.

23b. Bad Blades

A corroded steel helm rests atop a pile of rusty swords in the middle of the room. When another creature enters the room, the pile of swords gathers into a vaguely humanoid form with the helm surmounting it and attacks. This assemblage of rusty steel has the statistics of animated armor, except that its attacks deal piercing damage instead of bludgeoning damage.

23c. Rodent of Unusual Size

Every few hours, a brick of rotting meat slides down the chute from a hidden chamber above. The meat hits the floor with a wet smack and is promptly eaten by the monstrous rodent. A Tiny or gaseous creature can access this small, hidden chamber by climbing up the chute. There are no exits from the upper room, which contains only hundreds of bricks of pink, rotting meat and a magical mechanism that pushes them down the chute at random intervals. It's impossible to discern what sort of creature the meat has been harvested from.

23d. Guffaw the Stone Eater

This room contains the smashed remains of a dwarf statue and a plump deep gnome (svirfneblin) named Guffaw Gravelstock, who was plucked from his Underdark gem mine by Arcturia. He is unfamiliar with Undermountain.

Arcturia's magic has given the gnome an insatiable appetite for carved stone. He uses his war pick to break up the statue and is devouring it slowly, one piece at a time. He can't keep himself from stopping to eat any carved stone he sees—and there's no end to how much he can consume. He begs to be left alone so he can finish his meal in peace. A successful dispel magic spell (DC 19) cast on Guffaw rids him of his unique magical malady.

Arch Gate to Level 9

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

• Holding an open book while standing within 5 feet of the arch causes the gate to open for 1 minute. The book turns to dust as the gate opens, even if it is a spellbook.
• Characters must be 10th level or higher to pass through this gate (see "x"). The first creature to pass through the gate triggers an elder rune (see "x").
• A creature that passes through the gate appears in x, in the closest unoccupied space next to the identical gate located there.

Mithral Key

Characters who search the apprentice's robes find a 6-inch-long, flat piece of mithral shaped like a U in one pocket. This key is one of six required to activate the weapon of mass disintegration in x.

Table

Until recently, Arcturia had a mind flayer assistant. She tore off its head to study the psychic energy stored in its brain. Next to the head is a long pair of steel tweezers and a ladle.

The 1-foot black cube is an ebony-framed box fitted with panes of black glass. The box has a hinged lid and radiates an aura of transmutation magic under the scrutiny of a detect magic spell. When a Tiny beast small enough to fit in the box (such as a rat or a lizard) is placed inside and the lid is closed tightly, the box magically transforms it into some other Tiny beast (your choice) unless it succeeds on a DC 15 Wisdom saving throw. The box can do this eight more times before its magic is fully spent, whereupon it crumbles to sand.

The folded gray blanket upon which the box rests is, in fact, the carefully removed skin of a doppelganger. Other items on the table include a jar of cockatrice tongues, a block of soft clay (the material component for the stone shape spell) wrapped in moist cloth, and a wooden coffer labeled "Polymorph" containing a dozen caterpillar cocoons (material components for the polymorph spell).

Treasure

Hidden in the floor under the table is a small secret compartment that can be discovered with a successful DC 20 Wisdom (Perception) check. It contains a jade circlet worth 1,500 gp (the material component for a shapechange spell) and a spell scroll of polymorph.

32a. Soldiers' Quarters

Thirty hobgoblins rest in wooden bunk beds stacked three tiers high. There are enough beds to accommodate sixty guards. The hobgoblins sleep in their armor; their weapons and shields hang from hooks on the corners of their bunks.

32b. Guard Post

Four hobgoblins stand guard here—two flanking the door to x, and two flanking the door to area 32c. Any battle here brings reinforcements from those areas, as well as from x.

32c. Captains' Quarters

Two hobgoblin captains converse quietly in this room, which contains three beds. Other furnishings include a stone table surrounded by six wooden stools, with an unlit iron chandelier suspended above it.

The captains are worried about the recent abnormal behavior of their warlord commander (see area 33) and contemplating what to do about it. So far, the captains have hidden Doomcrown's bizarre preoccupations from the rest of the hobgoblin legion and remain, for the time being, loyal subordinates.

Treasure

The wooden trunk contains the hobgoblins' loot: 2,500 gp, an electrum pepper shaker (25 gp), a pewter candlestick (25 gp), a red velvet cape (50 gp), an ornate coral statuette of a ship cresting a wave (250 gp), a dwarven beard comb made of lapis lazuli and set with gemstones (750 gp), a platinum crown with black pearl inlay (2,500 gp), and an elven helm made of leafed gold with a spiral horn of amethyst protruding from its brow (7,500 gp).

Using the Mithral Keys

Six mithral keys are required to activate the chamber. Each conforms in shape to one of the six indentations in the walls, which are (from left to right, going clockwise around the room): an upside-down Y, a backward J with a small loop at the top, an upside-down F, an upside-down U, a V with a small loop at the bottom, and an H missing its top left stem. When the six keys (located in x, 71e, 72b, 752, and 776) are placed in their corresponding indentations, a magic mouth spell counts down from 20 seconds (in Common). At the end of the countdown, there is an ear-splitting whine, and a powerful spell deals 150 force damage to every creature on level 14 of Undermountain (no saving throw allowed). Any creature reduced to 0 hit points by this effect is immediately disintegrated and reduced to a pile of dust. The spell also disintegrates the six mithral keys.

Creatures that are standing in the lit alcoves when the spell goes off are unharmed, as are creatures inside an antimagic field. (The antimagic fields in x and 763 protect the creatures there.)

Trapped Chest

The chest has an iron key in its lock, and turning the key unlocks it. A detect magic spell reveals an aura of transmutation magic emanating from inside the chest.

The chest is empty except for a magic mirror fastened to the inside of its lid. Any creature that sees its reflection in the mirror is targeted by a flesh to stone spell (save DC 20). Once the spell has been triggered, the mirror ceases to be magical.

Treasure

The crystal decanter is worth 250 gp but is fragile. It contains cheap wine. The owlbear rug is worth 75 gp.

39a. Gold and Black Boudoir

The rakshasa is bound to these boudoirs and can't travel beyond x, even through the use of spells, as long as the circular seal above the doors remains in place. (Spells that would transport the rakshasa away from the area simply fail.) Arcturia trapped the rakshasa here years ago and draws blood from the fiend to fuel her terrible transmutation rituals.

Alussiarr has no beef with the adventurers and doesn't want to distress them by revealing its true form. It does, however, ask them to set it free by breaking the seal outside the room. If the characters do so, the rakshasa turns invisible and makes its way out of Undermountain with the goal of working all manner of evil in Waterdeep—but not before telling the heroes where they can find Arcturia's spellbook (x) and phylactery (x), as well as the command word to reveal the bookshelves in x. It also gives them a flat, 6-inch-long mithral key shaped like a Y, and tells them it's one of six keys required to activate the weapon of mass disintegration in x. Alussiarr doesn't know where the other five keys are kept.

If the characters haggle with the rakshasa, it also vows to provide up to three additional pieces of useful information in exchange for its freedom, such as the way to level 15. If the characters refuse to help Alussiarr, the rakshasa shrugs its shoulders, returns to its nap, and gives them nothing in return. It has waited years to escape—it can wait a few more.

39b. Skull and Bone Boudoir

39c. Crystalight Boudoir

The living unseen servant plays the harpsichord tirelessly and fights only in self-defense.

A detect magic spell reveals auras of transmutation magic around the dancers who, in truth, are a mated pair of young blue dragons. The dragons are Arcturia's guests, and their names are Nystalancer and Venasorrn. With the help of Arcturia's magic, they are experiencing what it's like to be human and pay no attention to new arrivals. If the music stops or either of them is touched or harmed by another creature, the dragons revert to their true forms simultaneously and attack. Their clothing and jewelry merge into their new forms. Arcturiadoom is not their lair, and they keep no treasure here.

40a. Sentinel Statue

The dwarf statue is inseparable from its base, and its base is inseparable from the floor. If anyone other than Arcturia opens the secret door, the statue transforms into a 6-inch-thick wall of stone that bisects the room from east to west, creating separate chambers to the north and south. The wall is permanent. Each 10-foot-square section of it has AC 15, 180 hit points, and immunity to poison and psychic damage.

40b. Arcturia's Library

A detect magic spell reveals auras of transmutation magic around the pedestal and rectangular sections of the north wall where hidden bookshelves magically emerge (see "Treasure" below).

The pedestal is a Small object with AC 15, 20 hit points, and immunity to poison and psychic damage. Under certain conditions, it transforms into a nalfeshnee (see area 40c). The pedestal also transforms if it takes damage. With Halaster's help, Arcturia pressed the demon into service. Its primary task is to guard the lich's phylactery. While in pedestal form, the demon is unaffected by the weapon of mass disintegration in x.

40c. Arcturia's Phylactery

A niche in the north wall holds a small box made of purple crystal—Arcturia's phylactery. The phylactery does not detect as magical. If the characters remove the phylactery from this room, the demonic pedestal in x transforms into a nalfeshnee and attacks them.

Destroying this phylactery leaves Arcturia with no means to rejuvenate once her physical form is destroyed. The object can be destroyed only after being digested in the stomach of a mimic for three days. A legend lore spell or similar magic reveals the exact method of the phylactery's destruction.