Out of the Abyss

Labyrinth Encounters

This chapter features a number of set encounters. Either as the characters journey to the Labyrinth or return to Vizeran's tower, you can run the "x" encounter. Once the characters reach the edge of the Labyrinth, go to the "Spiral of the Horned Lord" encounter.

Within the Labyrinth, the characters take on the encounters "x," "x," "x," and "x" (their intended destination). They might also take on "x" encounter, inspired by knowledge gained in x and an encounter with some modrons in the Labyrinth.

Adamantine Tower

The adventurers come across a tower haunted by forces of darkness.

No ordinary structure, the tower is a Daern's instant fortress (see chapter 7, "Treasure," of the Dungeon Master's Guide). Made entirely of adamantine, the two-story tower has remained sealed since its last owner retreated inside and locked the door behind her—but not before a pair of shadow demons slipped in as well. The demons killed the owner and left her remains on the first floor. The tower can't be tipped over or otherwise moved from its position, and the arrow slits on each level are too narrow for anything bigger than a Tiny creature to squeeze through.

A character can learn the tower's command words by casting an identify spell on it. The command word to open the front door or the trap door on the roof is "mimsy." The command word to transform the tower into a one-inch metal cube is "brillig," but speaking it has no effect since the shadow demons are still inside. To return the tower to its cube form, the adventurers must first empty it of any creatures.

Four gargoyles perch atop the tower. They remain motionless as the characters enter the cavern, attacking only if anyone attempts to enter, climb, or damage the tower.

This cavern's rough floor has been flattened where the tower stands, while the floor behind the tower has collapsed into a shaft 300 feet deep and 100 feet in diameter. Several tunnels branch off from the rough-walled shaft at various points, allowing the characters to continue their journey after climbing down. They can move around the tower easily if they wish to ignore it.

Spiral of the Horned King

Minotaurs have roamed the tunnels of the Labyrinth for ages, but as Baphomet's influence grows, so too has the ferocity of his chosen servants. The waxing of Baphomet's power has not gone unnoticed by the packs of gnolls rampaging through the Underdark. The gnolls have begun making inroads into minotaur territory. The latest battlefield in the ancient feud between Baphomet and Yeenoghu is a maze of passages that grant access to the deeper passages of the Labyrinth.

The cleft leads to the Spiral of the Horned King—a maze of tunnels and caves along the outer edge of the Labyrinth. Though other routes can be found into the Labyrinth, this entrance is the easiest to find.

Invocations to Baphomet, dire curses, and the inverted names of the gods are scrawled around the cleft in dried blood, and continue on down the tunnel walls. Anyone who can read the Abyssal tongue can tell that this place has been consecrated in the name of Baphomet, the Horned King and lord of minotaurs.

The minotaurs tear off their victims' heads, then leave them to "watch" the entrance for intruders. Most of the heads are from gnolls, though different Underdark races can be found if any character wants to sift through the piles.

Filthriddens

Filthriddens was, until recently, a shanty town of Underdark exiles and refugees. The greatest threat to inhabitants—apart from food shortages—was the minotaurs that raided the settlement from time to time, dragging off screaming prisoners to meet a grisly fate. The recent arrival of the demon lords changed things. A group of minotaurs was on its way to raid Filthriddens when Yeenoghu and a pack of his frenzied followers tore through this part of the Labyrinth, catching the minotaurs off guard and slaughtering them. The sole witness to this carnage was Grisha, an escaped human slave of the drow. Yeenoghu's intercession saved him from the minotaurs.

Yeenoghu and his pack moved on, but Grisha took the head of a slain minotaur and brought it back to Filthriddens. The skull became a talisman as Grisha named Yeenoghu as the new protector and patron of Filthriddens. Residents who opposed this dark worship were exiled or executed in short order. The cult of Yeenoghu now controls the settlement, and Grisha rules with an iron fist. He senses the power of Yeenoghu in all things—and particularly in the way in which cultists have begun to rise as undead ghouls after death.

March to Nowhere

The Labyrinth is aptly named, for even the most resolute of explorers can become lost in its depths, as a number of modrons discovered to their dismay. Separated long ago from their fellows during the Great Modron March, these modrons have been wandering the Underdark for a long time.

As the party travels deeper into the Labyrinth, any character with a passive Wisdom (Perception) score of 15 or higher hears the sounds of marching feet off in the distance. To investigate the source of the noise, the characters must travel for 15 minutes through cramped tunnels requiring as much climbing as crawling. At the end of this time, the adventurers emerge onto a shelf 15 feet up the wall of a broad, straight tunnel some 20 feet high.

Twelve monodrones and a tridrone have been wandering the Labyrinth since the last Great Modron March. The modrons became separated from their fellows and trapped here. Unable to find their way back to Mechanus, the modrons have been pressing on (and on), knowing that they must find their way back or be destroyed in the process.

The extended march has taxed the modrons to their limit. Most show signs of the frustration of being unable to fulfill their mission. The tridrone has managed to keep the group together, but it feels responsible for their collective fate and their failure to return home. Even if the characters have the ability to communicate with the modrons, the monodrones' ability to communicate is all but spent (see the "Roleplaying the Modrons" sidebar).

The tridrone can be very communicative—provided the characters have a way to speak with it and can allay its suspicions. A character can persuade the tridrone of the party's good intentions with a successful DC 15 Charisma (Persuasion) check. They have advantage on the check if the party includes one or more modrons.

Once convinced of the characters' friendly intentions, the tridrone tells them that it and its fellows are on a mission of supreme importance, though it doesn't reveal the nature of that mission. A character can puzzle out the reason why the modrons might be here by making a DC 20 Intelligence (Arcana) check. Success indicates that the character recalls stories about the Great Modron March, which occurs every 289 years and sees a vast army of modrons marching across the Outer Planes. If the check succeeds by 5 or more, the character also knows the last march happened over two hundred years ago, and that these modrons are likely remnants of that march. The tridrone doesn't admit this (not wanting to acknowledge its failure), though it might be convinced to follow the characters if they offer to lead the modrons out of the Labyrinth. Additionally, the tridrone knows the Labyrinth well, and befriending the modrons grants characters a +5 bonus to Wisdom (Survival) checks made to navigate the region.

The tridrone warns the characters to avoid the center of the Labyrinth, explaining that a malfunctioning "Orderer" is there. The characters might know the device by its other name: the Maze Engine. Because the device was built on Mechanus, its magical energy resonates with the modrons. The tridrone explains that an Orderer is designed to bring order to chaos by altering reality. A malfunctioning Orderer can be very dangerous, however, altering reality in unexpected ways. The tridrone knows exactly how far it is from the device. Because its knowledge of magic is limited and its focus on rejoining the Great Modron March is all-consuming, the tridrone has never thought about whether the Orderer might provide a solution to the modrons' predicament. If the characters express an interest in investigating this possibility, the tridrone leads the party to the center of the Labyrinth where the Maze Engine is found.

Yeenoghu's Hunt

About twelve miles from their encounter with the modrons, as they travel through the Labyrinth, the characters hear sounds of howling in the distance off and on over the course of many hours. Sometimes the sounds get closer or fade away, echoing strangely through the surrounding tunnels.

Eventually, the characters enter a smaller tunnel leading upward. As they move forward, they can clearly hear the sound of fighting ahead. Bestial howls and yips can be heard, along with deeper roaring. A successful DC 13 Intelligence check recognizes the language of the battle cries as Gnoll. The characters can retreat away from the sounds of combat, but doing so means backtracking for six miles to find another route. If they continue ahead, they are confronted with a grisly scene. Though the characters likely have no firsthand experience of a goristro, they recognize the creature from the information provided to them by Vizeran DeVir.

Any adventurer witnessing this horrible tableau must succeed on a DC 12 Wisdom saving throw or gain one level of madness (see "x" in chapter 2). If this causes the character to suffer a bout of indefinite madness, determine the nature of the madness using the Madness of Yeenoghu table in appendix D.

Yeenoghu (see appendix D) has been wandering the Underdark since he was first summoned, and the adventurers have run across him and his pack. The characters' only advantage at this moment is that they haven't yet been detected. Considering their level at this stage of the adventure, the players might be creating new characters quite soon if they dare confront the demon lord.

If the characters stay hidden and observe, Yeenoghu leaves in short order. He is restless and eager for new prey. Yeenoghu gathers up most of the gnolls and hyenas and leads them down a tunnel on the right side of the cavern. Eight gnolls led by a gnoll pack lord remain in the cavern, feasting on the goristro's corpse.

If the characters want to continue forward, the gnolls and hyenas need to be dealt with. Alternatively, if the characters are indecisive or spend too long debating the best course of action, the gnoll pack lord sniffs out the intruders. When it realizes that enemies are present, the pack lord howls to draw the attention of its followers.

Gallery of Angels

This cavern lies deep inside the Labyrinth and contains another ritual component that Vizeran needs.

This chamber houses the petrified remains of eight fallen angels, condemned by the gods to pass the ages in the dark depths. Each appears to have been carved from stone in some position of fear, suffering, hatred, or longing. Each statue is spotted with lichen and marred by mineral deposits, which have crystallized out of the water dripping from the ceiling over uncounted years.

Even though they are transformed into stone statues, the fallen angels remain very much alive, their petrified bodies having become prisons for their minds and souls. They remember who they were. They know what they did and why they are here. They know everything transpiring around them. Yet they can do nothing. They are trapped forever, and the isolation, darkness, and endless torment of their fate have driven them mad. No spell can undo the angels' curse or free them from their petrified state.

The Maze Engine

Deep within the Labyrinth lies the Maze Engine—a mechanical, magically powered device capable of altering reality. Modrons refer to the device as an Orderer because it was designed is to bring order to chaos. If the characters activate the Maze Engine, it has the potential to aid their fight against the demon lords.

The engine looks like a working model of the Great Wheel (see chapter 2, "Creating a Multiverse," in the Dungeon Master's Guide). It's a 20-foot-diameter sphere built of 1-foot-wide bands of magically hardened and shaped bronze, engraved with arcane symbols. Gaps in the bands show various gears and articulation arms within the sphere, which rotate and shift to represent the relationships between the various known planes of existence.

Characters might learn about the existence of the Maze Engine from the beholder Karazikar (see x) or from Vizeran, who has heard rumors about an ancient reality-altering device. Characters might also learn about the engine from Karazikar's modron prisoner or from the modrons lost in the Labyrinth (see "x").

Information about the Maze Engine can also be found in Gravenhollow (see x). The characters could experience a vision of a journey to the Labyrinth in the library, or read an account of the device in its archives.