DotMM: New Neighbours

If you play Dungeon of the Mad Mage as an open-table campaign where sessions represent excursions that are potentially months apart, you’ll want to repopulate the dungeon between games.

The following tables provide some inspirational encounters for each level of the dungeon. The majority of the encounters here fall within the easy-hard range for their level.

Enjoy!

Level 1: Dungeon Level

The Deep Druids

It’s not clear how these creepy cultists find their way into the dungeon, but they sure waste no time filling it with all kinds of gross plants and bugs. Poisonous fungi, yellow mold (see Dungeon Hazards in the DMG), nasty giant insects, evil trees, and weird stick effigies start filling rooms. Every full moon they dance naked in their secret sanctum, around an underground Gulthias treant that looks a little bit like Halaster.

Level 2: Arcane Chambers

The Gauth

The wealth of magical residue in the Arcane Chambers attracts these extraplanar scavengers. Two of them make their way in through a broken summoning portal: Qorbysalk, whose skin is a sickening shade of fuchsia that sheds dim to bright light depending on when it last ate, and Xozysalk, a blubbery gray brute whose eye-stalks are as thick (and powerful) as arms, and who likes to chew on wands and swords after draining their power, grinding them between multiple rows of adamantium-capped teeth. Together they bully lesser dungeon inhabitants like the goblins, xanathar tugs, wererats, or nothics into service and have them scour the level for magical trinkets to sate their hunger.

Gauth Spawn. A slain gauth emits a wave of magical energy but doesn’t physically explode. In fact, if the body is not properly disposed of, two identical but smaller gauths emerge within a week. The new monsters have half their parent’s hit points and use one less eye beam attack each round. Gauths with less than 20 starting hit points do not spawn offspring in this way.

Level 3: Sargauth Level

Skullport treasure hunters

Those who follow the river Sargauth to the north for about a mile arrive at a sandy cavern with a crumbling fortress. Death tyrants guard a long-dead elder beholder’s hidden vaults in the ruins. If the drow and goblinoids’ forces are diminished, chancers from Skullport travel the river in expeditions to the old stronghold.

Level 4: Twisted Caverns

Demonic Insurgence

Summoned by desperate drow, deranged kuo-toa rituals, or an early strike force for the Blood Wars, the Twisted Caverns are ripe for a demonic invasion. Rooms take on abyssal qualities such as demonic fog, layers of skulls, walls oozing slime. Dretches and manes mill about aimlessly waiting for higher-tier demons to round them up and send them on one of the increasingly numerous assaults on whatever faction is still alive. When all that is left are demons, they summon a straight-up balor which carves out its own slice of Abyss, right here in Undermountain.

Level 5: Wyllowwood

The Necromancer

Soon she will exact sweet revenge on those who would murder her people. Cold and calculated, she is content to let adventurers pass through her domain while she slowly amasses her legions. She has a manual of reanimating dragons, but nowhere near the 50,000gp required to complete the ritual. Yet.

Level 6: The Lost Level

Halaster’s Trolling

Halaster likes to fill this level with random monstrosities to keep Bandaerl busy. Read the following:

Suddenly, a cracking but powerful voice comes from deep in the dungeon! “Dumetheir! Have you been lonely, little dwarf? Here are some more friends to accompany you!”

With that, a huge pair of glowing, ephemeral hands appear and unleash a wild flurry of mist and energy! Energy bolts both large and small flow through exits and out of sight. One arc of energy lands in the center of the room and begins shifting into three large forms!

The arc forms into 3 ettins.

Bandaerl Dumatheir, last protector of the melairkyn

Bandaerl looks like a dwarf made out of rock: light gray and with a beard like stalactites. He is the last priest of Dumathoin, closing and guarding the temple millennia ago so that others could escape. For his piety, Dumathoin has blessed him with archlich status.

Bandaerl offers friends of the clan aid, advice, and a place to rest. Graverobbers are not considered friends of the clan.

Level 7: Maddgoth’s Castle

Yeti Tribe

Halaster freezes the caverns and fills them with a tribe of yetis led by a pair of mated abominable yetis. The group sports a pet white dragon, which they have raised from birth. It’s becoming recalcitrant in its juvenile years.

Level 8: Slitherswamp

The Flood

A Dweomercore experiment gone wrong, torrents of ooze flood the level. A trail of green slime (see Dungeon Hazards in the DMG) marks the path of the spill as it moves to engulf this level of the dungeon. There is a strange intelligence behind the flow of these normally mindless creatures – an elder oblex (see Mordenkainen’s Tome Of Foes) makes its throne deep in the swamps. The wizard Karstis is dead, and now one of the oblex’ first personalities.

Level 9: Dweomercore

The cursed pasha

Without a headmaster, Dweomercore will certainly devolve into an abandoned battleground. And who is there to fill the vacuum? None other than Dhalmashrus, a Calishite prince who made a deal with the devil and was turned into a rakshasa but cursed to never see his loved ones again – for an unyielding craving for living flesh overcomes him whenever he lays eyes on a humanoid. Dhalmashrus dresses like a Calishite noble, including a silken headscarf and white finery with elaborate golden patterns. He quickly redecorates the school as his personal palace and brings in his substantial entourage – of which all members look human but none are.

Level 10: Muiral’s Gauntlet

Muiral (aftermath)

Muiral reanimates the corpses of house Auvryndar’s drow and troglodytes and scatters them throughout the level, but he gives it that extra little bit of oomph this time. Intelligent undead, particularly vampires and revenants, remember the adventurers that killed them all too well.

Level 11: Troglodyte Warren

More troglodytes

While the elves and monsters can be dealt crippling blows, the troglodytes only grow in number, making their way in from elsewhere in Undermountain – growing ever bolder and more hostile.

Level 12: Maze Level

The Medusae

Life-like statues of minotaurs and drow start appearing in the dungeon as the last heir of the Ambergul estate moves in. Most of this family of disgraced tomb robbers are rotting in crypts under their ruined mansion, except for Olivine Ambergul. For her sins, the gods cursed her to roam Ambergul’s lands forever as a monstrous medusa. There she gained a following and piqued the Mad Mage’s interests.

Halaster invites her and her “sisters” into Undermountain with the promise of adventurers to slay and riches to steal. Olivine wears an iron medallion that she believes contains the spirit of her mother Alicia, and she sometimes speaks in her voice. Alicia enjoys parlaying with visitors and fights only in self-defense while Olivine’s only desire is to turn them to stone and display them in her gallery. A debased cult of grimlocks treat the medusae like gods.

Level 13: Trobriand’s Graveyard

Rust Zox

The arch backfires because of course it does. The end result is an evil metal simulacrum of Zox taking over this level, with the real zox dead or stuffed in an anti-magic hexahedron somewhere. Rust Zox (NE medium iron golem with the spellcasting abilities of a mage) begins to create an unending stream of scaladar, scouring the dungeon in search of powerful creatures from which to spawn rust simulacra. Rust Zox assimilates previous levels of the dungeon at a rate of one per 30 days until, after one year, a metal army emerges from the Yawning Portal, destroys Waterdeep, and spills out into the Sword Coast. Inhabitants of the dungeon start sending emissaries to warn Waterdeep of its impending doom. Halaster takes a “let’s see how this plays out” approach to the whole thing.

Rust modifier

+2 Str, +4 Con, -6 Int, -6 Cha.

Damage Resistances: fire; bludgeoning, piercing, and slashing from nonmagical attacks

Damage Immunities: force, lightning, poison

Condition Immunities: charmed, paralyzed, poisoned

Senses: darkvision 60 ft.

Lightning Absorption: Whenever this creature is subjected to lightning damage, it takes no damage, and its next attack deals an extra 11 (2d10) lightning damage.

Level 14: Arcturiadoom

Animalheads

Sure, Arcturia might forge an alliance with the mind flayers and Halaster might summon some azers to finish his crazy mechwarrior, and we could whip up a few level-appropriate encounters for each (1 mind flayer + 2 grell, 5 quaggoths controlled by intellect devourers, 2 mind flayers + 1 mind witness, 2 mind flayers + 2 quaggoths, 4 azers + 1 fire elemental, 2 azers + 2 shield guardians, 1 iron golem, 3 azers + 4 lava children) but that’s all so terribly mundane.

No, Arcturia is all about the animalheads – animals transmutated into humanoids with only their original head remaining. They can’t speak and know no languages beyond simple commands, but a speak with animals spell is surprisingly effective. Animalheads fear Arcturia beyond anything else and when communicated with using the aforementioned spell refer to her as “the worms that walk” – one of her more unsettling forms and the way in which she re-appears at her phylactery. Their orders are to prevent adventurers from taking any of the level’s treasures, so characters that leave Arcturia’s stuff alone should be fine.

Level 15: Obstacle Course

Several beholders

There’s a hidden room in the Obstacle Course. Large metal beams run across the ceiling, teeming with thick cables. In its center, an adamantium helmet hangs suspended from pulsating wires. The “dreamcatcher” is what Halaster calls it. He straps a beholder into the contraption and locks it in magical slumber. The device enhances the reality-warping properties of the aberration’s dreams and causes new beholders to appear out of thin air on random locations in the dungeon at a rate of one per tenday. Luckily their paranoid infighting keeps the population stable.

Volo’s Guide to Monsters has a great section on randomizing beholders. Here’s a few we’ve rolled earlier:

• Thimnoll, warty gray, pretends to be insane to trick its enemies.
• Derukoskai, pitted pink, strives endlessly to be better than perfect.
• Velxer, smooth mottled pink, dreams of creating a clone army of itself.
• Zalshox, scaled green and pink, regularly takes its frustration out on its minions.

Level 16: Crystal Labyrinth

Every month or so a spelljamming ship bearing provisions arrives at Stardock.

Space Gnomes

Their ship is cobbled together from spare parts and has a 50% chance of crash landing. All gnomes have darkvision and advantage on saving throws against magic.

Crew: Captain Caramip Tomenook (LN gnome mage), Fablen Tomenook (illusionist, see Volo’s Guide To Monsters), Cockaby Tomenook (illusionist), Ramana Tomenook (illusionist), 6 officers (veteran), 3 priests, 10 scouts, 15 guards.

Space Scro

They try to commandeer Stardock if they smell any weakness.

Crew: The initial envoy consists of captain Dukagsh (orc war chief), chief advisor Munuka (polymorphed oni), 3 war priests (orc eye of gruumsh), and 3 sergeants (orog).

Remaining on board of the ship are 50 orcs, 10 orogs and 6 orc eyes of gruumsh.

Space Giff

Expect to be paid in gunpowder upon delivery.

Crew: 1 respected captain (giff, see Volo’s Guide To Monsters, with 88 hp, two actions per turn, and seemingly unlimited grenades that can be thrown as a Bonus Action), 1 noble helmsman (giff), 1 puissant crafter (giff), 1 master gunsman (giff), 20 additional giff, 1 hired mage to operate the helm.

Space Lizardfolk

Unlike their Toril-based cousins, space lizardfolk are highly civilized and intelligent, and tend to secretly infiltrate the governments of lesser races.

Crew: Their vessel is relatively small and crewed by a captain (lizard king/queen), four lizardfolk shaman, and 10 lizardfolk. They wield laser pistols that they can use instead of a claw attack for 3d6 radiant damage (range 40/120). See Adventuring Options in chapter 9 of the Dungeon Master’s Guide for details.

Level 17: Seadeeps

They don’t call it the seadeeps for nothing

An endlessly long cavern leads to the Melairkyn dwarves’ primary mining location in the west, deep beneath the Sea of Swords. Halaster opens the valves and gates that have for millennia stopped the seawater from rushing in and floods the entire level. Halaster installs permanent walls of force to stop the water from spilling into Vanrakdoom, the Crystal Labyrinth, and the extended dungeon. Even when dispelled, these walls reappear within 1d4 turns. He then wastes no time populating his new subterranean aquarium with sea monsters, sunken ships, and a sahuagin fortress made from coral.

The coral palace

Providing a map for the sahuagin palace is beyond the scope of this blog – but I’d recommend the one in The Final Enemy, available on DMsGuild.com or as part of Ghosts of Saltmarsh. The hold of the storm giants in Storm King’s Thunder could also be repurposed for this use.

Level 18: Vanrakdoom

Faerie

Halaster, not one to grieve over the loss of his spooky castle, decides to go about it in a different way. When you think about it, the feywild and the shadowfell are just two sides of the same coin, right? The areas that were once in the shadowfell are now suffused with faerie magic. Broken furniture is replaced by beautiful craftsmanship with elegant upholstery, damp caves become sparkling grottos, some larger areas seem to have open ceilings that look out into eternal twilight. Gardens full of life fill the dungeon.

Also, leaving these areas causes amnesia and shifts time, see “Optional Rules: Feywild Magic” in chapter 2 of the Dungeon Master’s Guide. Should a party spend more than a month in the dungeon, the DM is encouraged to remove those characters from the ongoing campaign until the game’s time catches up with them.

Level 19: Caverns of Ooze

Deshif The Brilliant

The efreet’s cavern is dominated by a pool of lava, with a steel grate running across to his brass throne. The rising heat from the lava deals 1d6 fire damage per turn to any creature standing on this walkway, and a creature that befalls the misfortune of losing its footing and slipping into the lava takes 10d6 fire damage per turn. He is accompanied by two salamander bodyguards.

With Ezzat’s phylactery out of the picture, the genies have a new quest to give adventurers: a long time ago an adventurer entered Undermountain and made off with a sizable amount of loot. If the characters retrieve a sword of sharpness called Grimvault from this adventurer and return it to either remaining genie, that creature will be set free by Halaster and provide the characters with a fitting reward. In the case of Deshif the Brilliant this reward is a gem of brightness.

Welcome to the pit!

Marvel at my bazaar

Deshif they call me brilliant

Like a shining red star

You’re playing with fire

Is it hot enough for you?

Deshif they call me brilliant

I will tolerate no fools

I’m too hot to handle

I am burning down the house

Deshif they call me brilliant

I’ll never be doused

I drink liquid gold

I’ve got money left to burn

Deshif they call me brilliant

What is your main concern?

Level 20: Runestone Caverns

More Demons

I can see how you’d think Halaster managed to snare a demon lord – what with the dual wolf and snake heads. But even immortal mega-dungeon mages have their limits. Still though, a molydeus speaks directly for its master, is very powerful, and is extremely pissed off at being bound to the runestone caverns. In almost un-demonlike fashion it will plead, beg, and barter with the characters to help it escape back to the abyss.

Level 21: Terminus Level

Sphinx’s Riddle

Selune’s chariot orbits Toril at an unimaginable speed. What would make a man move at the same speed?

Riding her chariot.

You have been sentenced to death. Choose one of three rooms: one is constantly on fire, one holds a heavily armed assassin, and one is filled with predatory animals that haven’t eaten for years.

The animals are all dead.

When I am shared I am no longer myself. What am I?

A secret.

What is yours but mostly used by others?

Your name.

Speaking my name will pierce me, what am I?

Silence.

Level 22: Shadowdusk Hold

Level 23: Mad Wizard’s Lair

Kobolds

Halaster’s stronghold has been breached, it’s time to shore up security. He recruits a tribe of the most ferocious and feared monsters in all of the planes. The kobolds honeycomb the level with small tunnels to speed their movements and pepper the area with traps and ambushes. They assault intruders relentlessly and without mercy.