Waterdeep: Dungeon of the Mad Mage

Enemies at the Gates

Through methods unknown to the illithids, the githyanki vanguard force tracked the survivors of their attack on the colony to Undermountain. Having recently secured the nearby Crystal Labyrinth (level 16), the githyanki now wage war against the mind flayers in Seadeeps. Uncertainty about its own future has forced Extremiton to hold off on transforming into an elder brain. Instead, it is focused on defending the colony and destroying its githyanki neighbors. With only a dozen mind flayers remaining under its rule, Extremiton has resorted to breeding a neothelid (see appendix A) and plans to set it loose in the Crystal Labyrinth to finally wipe out the githyanki force. Extremiton is also gathering thralls of every race to help defend the colony if the neothelid is destroyed or fails in its task.

City of the Mind

Extremiton can sense intelligent creatures within 2 miles of it and is able to communicate with them telepathically. Using this ability judiciously, the ulitharid has learned a great deal about the city above and its inhabitants. Waterdeep has, in a way, captured the ulitharid's imagination.

Extremiton intends to enslave the population of Waterdeep, but not before it fully understands this strange city and its people. The telepathic communications the ulitharid has initiated with random Waterdavians has provided it with plenty of information, but no firsthand knowledge of how city dwellers behave and react on a daily basis.

In the heart of Seadeeps, the ulitharid has built an enormous dynamo that channels the energy of an underground river to power a series of interconnected metal capsules called psipods. The illithids under Extremiton's command have kidnapped humanoids from Waterdeep and Undermountain and put them to sleep in these capsules, which link their dreaming minds to the ulitharid's dizzying intellect. These captives believe they're in Waterdeep, but the city they see and experience around them is a fabrication created wholly by the ulitharid. Within this alternate reality Waterdeep, or "Alterdeep," Extremiton appears as any character it wants. Its favorite role to play is that of Durnan, the gruff, tight-lipped proprietor of the Yawning Portal.

Extremiton can make any environmental changes to Alterdeep and observe how its captive audience reacts. Meanwhile, it continues to use its telepathy to reach out to the Waterdavians in the city above, gathering more information to better realize its version of the city.

Pit Trap

A detect magic spell reveals an aura of transmutation magic around the pit. Each time part of the statue is disturbed, the pit magically snaps shut like a giant mouth and then slowly opens again. Creatures in the pit when it closes are crushed between its rocky walls and must make a DC 17 Dexterity saving throw, taking 88 (16d10) bludgeoning damage on a failed save, or half as much damage on a successful one. Creatures that are gaseous, amorphous (such as an ooze), or protected by an impenetrable magical barrier (such as that created by an Otiluke's resilient sphere spell) take no damage.

6a. Cave of Carnage

The githyanki report to the knights in x. Three fight to the death to defend the cavern, while the fourth retreats to x to alert their allies.

6b. Severed Heads

6c. One Brave Flumph

A flumph lurks in the shadows of this alcove, surreptitiously feeding on the psionic energy of the githyanki warriors in area 6a. A successful DC 12 Wisdom (Perception) check is required to detect the creature. The flumph has the same helpful disposition and information as the rest of its kin on this level (see x).

7a. Arch Gate to Level 15

The githyanki warriors follow orders without question and have no authority to negotiate; that task falls to the knights in area 7c. A fight here brings reinforcements from areas 7b and 7c.

7b. Barracks

The githyanki obey the knights in area 7c and won't accept healing from strangers without their superiors' consent.

The water spouting from the stone fish falls into the semicircular basin beneath it and drains out through small holes inside. The water is cool and clean, and serves the githyanki as a source of fresh water.

7c. Knights' Quarters

The older githyanki knight, Yaveklar, commands the githyanki forces on this level. Though she is eager to slay the ulitharid and wipe out the mind flayer colony, Yaveklar is cautious and patient. She has suffered more losses than her superiors would consider acceptable, so she's waiting for reinforcements before launching any further assaults.

The younger knight, Lashiir, stands ready to take over in the event that Yaveklar is removed from command. Lashiir is proposing to attack the neothelid in area 8, using misty step spells to bypass the walls of force containing it. Yaveklar is not convinced that her forces are strong enough to defeat the neothelid and still maintain a foothold on this level.

If the characters can communicate with the knights, they can attempt to forge a truce with the githyanki. Yaveklar orders them to slay the neothelid as proof of their worth. If the characters kill the neothelid but return to Yaveklar in a very weakened state, she takes advantage of their situation and tries to finish them off. If they kill the creature and return with strength to spare, Yaveklar agrees to let them travel through Seadeeps unmolested and will even commit forces to a joint operation to conquer the mind flayer colony. If Yaveklar is neutralized, Lashiir readily fills the power vacuum and behaves much like her predecessor.

The illithid head dangling from Yaveklar's belt is a trophy from a recent skirmish. Resourceful characters can animate the head and use its writhing tentacles to unlock doors equipped with Qualith locks (see "x").

8a. Neothelid's Cave

Magic walls of force seal off all tunnels leading to this enormous cavern (see "Walls of Force" below). The floor, while uneven throughout, has been worn smooth by the creature trapped here. The cavern has the following features:

Food in the form of humanoids is delivered to the neothelid through a stone door set into the east wall, beyond which is a smoothly carved tunnel leading to x. The door is sealed with a Qualith lock (see "x").

The neothelid is always hungry and tries to devour any creature that enters its cave. It lacks the intelligence to distinguish one kind of prey from another and feeds indiscriminately.

8b. Standing Gate to Level 19

In the middle of this otherwise empty cave is a pair of standing stones topped with a lintel, carved into which is a symbol of an arrow. The standing stones form a magic gate (see "x"). Its rules are as follows:

• If an arrow or a crossbow bolt is shot between the standing stones, the gate opens for 1 minute.
• Characters must be 15th 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.

8c. Dead-End Cave

The tunnel leading to this cave narrows dramatically, but not enough to keep the neothelid from reaching prey that flees here. The cave is empty.

Arch Gate to Level 14

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

• If three humanoids hold hands while standing within 5 feet of the gate, it opens for 1 minute.
• Characters must be 13th 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.

12a. South Water Collector

The ceiling in this chamber forms a dome 20 feet higher than the floor around the cistern, which is 10 feet deep. Water pouring in from the east travels north along a trough that leads toward x.

12b. East Water Collector

This area is watched by the ettins that lurk in x.

The ceiling in this chamber forms a dome 20 feet higher than the floor around the cistern, which is 15 feet deep. Water pouring in from the south travels west along a trough that leads toward area 12c. Excess water flows north through a submerged tunnel blocked by a 10-foot-diameter, circular iron grate that Tiny creatures can slip through. Forcing open the grate while fighting off the current requires a successful DC 30 Strength (Athletics) check.

12c. Central Hub

The ceiling in this chamber forms a dome 40 feet higher than the floor around the cistern, which is 20 feet deep and fed by a submerged tunnel to the southeast. Water also pours in from 10-foot-deep troughs to the south and east, and forced westward and northward along troughs that lead to areas 12d and 12e, respectively.

12d. West Water Collector

The ceiling in this chamber forms a dome 20 feet higher than the floor around the cistern, which is 30 feet deep. Water pouring in from the east exits through a submerged tunnel in the north wall of the cistern, 20 feet below the water's surface.

12e. North Water Collector

The ceiling in this chamber forms a dome 20 feet higher than the floor around the cistern, which is 40 feet deep. Water flowing in from the south and west exits through a submerged tunnel in the east wall of the cistern, 30 feet below the water's surface.

Two dead grimlocks float in the cistern, with the brains torn out of their skulls. This is where the mind flayers dispose of creatures they feed on. Eventually, the corpses sink and get swept downriver.

12f. Dining Experience

The stone door to this room is soundproof, airtight, and sealed with a Qualith door lock (see "x"). The ceiling is 10 feet high and flat. The room contains the following features:

Dining on brains is a spectator event for mind flayers. With the aid of telepathy, the diner can convey the pleasures of a meal to other illithids in range. These mind flayers don't like being outnumbered. They try to stun as many characters as possible, then gather reinforcements from area 12h.

Most of the grimlock's brain is consumed by the time the characters arrive. Short of a raise dead spell or similar magic, there's no way to save the creature from its fate.

12g. Control Room

The stone door to this room is soundproof, airtight, and sealed with a Qualith door lock (see "x"). The ceiling is 10 feet high and flat. The room contains the following features:

While seated in its crystal throne, Extremiton is psychically linked to the psipods in x and 8e3 and is maintaining its Waterdeep simulation (see "x"). If it leaves the throne, the simulation deactivates and the psipods shut down. When this happens, the mind flayers in x and 8e3 make their way here to find out why the ulitharid ended the simulation. It takes them 4 rounds to arrive.

Extremiton has enough on its mind without battling adventurers. If cornered here, it tries to negotiate a peaceful settlement. As a lawful evil creature, it tries to uphold its end of any agreement while twisting a badly worded deal to its advantage. Primarily, Extremiton is concerned with its own safety and the elimination of the githyanki. The welfare of the rest of the colony comes second. It places no value on prisoners and gladly releases them if doing so is enough to preserve its life.

The scene projected on the back wall is what Extremiton sees when it looks through the eyes of the virtual Durnan in the alternate version of Waterdeep. The view changes abruptly whenever the ulitharid switches characters in the simulation, and the scene fades entirely when the ulitharid leaves its throne.

Given a chance to do so, the ulitharid is delighted and eager to show off its Alterdeep simulation, which it is using to learn more about Waterdeep and its multifaceted culture. Extremiton fails to mention that once it becomes an elder brain, it plans to use its newfound knowledge to enslave the entire city.

12h. Ettin Thralls

This curved chamber has a flat ceiling 10 feet high. Lurking in the dark, empty alcoves to the north and south are four scrawny ettins. At full health, each ettin has 60 hit points.

The ettins' minds have been broken by dominate monster spells cast on them repeatedly by the illithids over many months. These drooling, gibbering, malnourished thralls won't attack illithids or creatures in their company. All other creatures are attacked on sight. The starving ettins hungrily devour any kills.

13a. Treasury

Two chests carved from zurkhwood sit atop low stone tables against the west wall of this room.

13b. Outer Guard Post

The north wall of this empty, unfurnished room contains a secret door.

Psipods

A psipod is a magic device that connects the mind of an unconscious humanoid to the mind of the ulitharid in area 12g. The psychic residue that coats each psipod is a byproduct of this connection. The residue is sticky and foul-smelling, but harmless. It dissolves after a few hours.

Any creature that enters a psipod's bronze cylinder must succeed on a DC 17 Constitution saving throw or fall unconscious, lulled into that state by a soothing psionic vibration that the ulitharid produces. A creature that succeeds on the saving throw must repeat it at the end of each of its turns unit it exits the cylinder.

While in a psipod, an unconscious creature finds itself drawn into a simulated reality created by the ulitharid (see the "Alterdeep" sidebar) and can survive in this state for the remainder of its natural life, its mind and body nourished by the psipod's psychic energy. If the psipod is shut down, or if the unconscious creature is removed from it, the creature can repeat the DC 17 Constitution saving throw at the end of each of its turns, waking on a success. The creature also awakens if it takes damage in the real world, but not if it takes damage in the Waterdeep simulation.

A psipod shuts down if it is disabled or destroyed. To disable a psipod, a creature must disconnect three of the eight copper wires connecting it to the metal panels in the floor. The mind flayers' schematic pads identify which three wires to disconnect on each psipod. (The combination of wires varies from one psipod to another.) If wires are torn out at random, roll a d8 three times (rerolling duplicate results) to determine which three wires shut down that particular psipod, then roll a d8 for each wire that is disconnected to see if it's one of the correct ones. Disconnecting a wrong wire triggers a magical surge that targets all creatures within 5 feet of the psipod except the one inside it. A targeted creature must make a DC 17 Wisdom saving throw, taking 22 (4d10) psychic damage on a failed save, or half as much damage on a successful one. A magical surge from one psipod has no effect on the others.

All the psipods shut down if the ulitharid dies or leaves the crystal throne in area 12g. Each psipod is a Large object with AC 15, 50 hit points, and immunity to poison and psychic damage. A creature inside a psipod has total cover against attacks originating from outside the capsule.

Unconscious Humanoids

Eight of the humanoids in the psipods are commoners of mixed race, alignment, and ethnicity. Their names are Daundarak Steelfist (LG male shield dwarf), Jarana Hammerstone (LG female shield dwarf), Falain Tlandrue (CG female moon elf), Merrily Shadowstep (NG female lightfoot halfling), Jagtar Uythrapp (LG male Mulan human), Lament (N male tiefling), Stormal Voss (LE male Illuskan human), and Lander Hellwind (CG male Illuskan human). All were abducted from Waterdeep. Apply racial traits to them as warranted, and remember that dwarves, elves, and tieflings have darkvision.

The ninth humanoid is Selphorn Amcathra (NE male Tethyrian human noble). A resident of the town of Amphail, he was abducted after attending the funeral of a cousin in Waterdeep. Selphorn promises a reward of 500 gp for his safe return to the City of Splendors and makes good on his promise, but he puts his self-interest above all other concerns. Characters from Waterdeep would know that House Amcathra is one of the city's wealthiest noble families.

16a. North Guard Post

The mind flayers gained control of two scaladar (see appendix A) and implanted duergar brains in them, bestowing on each construct an Intelligence of 11 and the ability to understand (but not speak) Dwarvish and Undercommon. Each duergar brain is contained in a glass sphere embedded in the construct's head. These scaladar obey the commands of illithids and attack any creatures that aren't mind flayers or their thralls. Trobriand's rings no longer have any effect on these constructs.

16b. South Guard Post

This misshapen, 20-foot-high room sits at the top of a sloped tunnel that descends for hundreds of feet to level 18. Guarding the otherwise empty room are eight duergar. If they see light approaching, the duergar turn invisible and enlarge themselves, then ambush anyone that enters the chamber. These duergar have had their minds broken by the mind flayers and fight to the death.

16c. Psionic Force Generator

The crystal pedestal with the diamond levitating above it is a psionic force generator, a magic device that allows the mind flayers to create and sustain the walls of force that enclose area 8. The mind flayers provide the mental energy that powers the generator. If these mind flayers are attacked, one maintains contact with the crystal pedestal while the other defends it.

The diamond no longer floats if removed from its place above the pedestal. A creature within reach of the diamond can use an action to take it. Without the diamond, the generator shuts down and the walls of force in x disappear. The device can't function without the diamond (or another of the same or greater value). The walls of force also disappear if the mind flayers are pulled away from the pedestal—though the walls reappear if contact is reestablished, as long as the diamond is still floating in place. If the walls disappear, the neothelid in area 8 escapes in search of prey, killing and consuming any creatures it finds.

The crystal pedestal is embedded in the floor and can't be knocked over, but it can be destroyed, rendering the generator irreparable. The pedestal is a Small object with AC 13, 20 hit points, and immunity to poison and psychic damage.

19a. River's Roar

Creatures in this 10-foot-high, partially collapsed chamber have disadvantage on Wisdom (Perception) checks that rely on hearing due to the loud roar of the underground river nearby.

19b. Safe Shoreline Cave

The 10-foot-high, rough-hewn chamber is strewn with rubble. The shore is rocky and covered with loose dirt.