INFINITE LAYERS
OF THE ABYSS

It is an infinity of clutching horror.
It is home to demons.
It is where morality crumbles and ethics perish.
The Abyss is all that is ugly, all that is evil, and all that is chaotic reflected in infinite variety through layers beyond count. Its virtually endless layers spiral downward into ever more atrocious forms. Conventional wisdom places the number of layers of the Abyss at 666, though there may be far more. The whole point of the Abyss, after all, is that it's far more terrible than conventional wisdom could ever encompass.
Each layer of the Abyss has its own unique, horrific environment. No theme unifies the multifarious layers other than their harsh, inhospitable nature. Lakes of caustic acid, clouds of noxious fumes, caverns of razorsharp spikes, and landscapes of magma are all possibilities. So are less immediately deadly terrains such as parched salt deserts, subtly poisonous winds, and plains of biting insects. The Abyss is home to demons, creatures devoted to death and destruction. A demon in the Abyss looks upon visitors as food or a source of amusement. Some see powerful visitors as potential recruits (willing or not) in the never-ending war that pits demons against devils: the Blood War.
Demon lords and deities inhabit the Abyss, including Demogorgon, Graz'zt, Pazuzu, Blibdoolpoolp (deity of kuotoa), Diirinka (deity of the derro), the Great Mother (deity of beholders), Gruumsh (deity of orcs), Hruggek (deity of bugbears), and many others, including the well-known deity Lolth (draw deity and queen of the demonweb pits).
Other demon princes include Yeenoghu, Alzrius, Baphomet, Eldanoth, Fraz Urblu, Juiblex, Kostchtchie, Lissa'aera, Lupercio, Lynkhab, Pale Night, Verin, and Vucarik.
As noted before, the Abyss has layers beyond count, though the top layer is well-known: the Plain of Infinite Portals.

ABYSSAL TRAITS

The Abyss has the following traits.
 Normal Gravity: The top layer of the Abyss, the Plain of Infinite Portals, and many other layers have the normal gravity trait, but other layers of the Abyss can contain wildly different gravity traits that run the gamut of possibilities.
 Normal Time: Time flows at the same rate in the Abyss as on the Material Plane. However, rumors persist of a layer where time flows backward with regard to aging. The reverse flow is erratic, however, and a visitor could be reverse-aged to childhood or out of existence altogether.
 Infinite Size: The Abyss goes on forever in the form of an infinite number of layers, although its well-known realms are bounded.
 Divinely Morphic: Entities at least as powerful as lesser deities can alter the Abyss. Less powerful creatures find the Abyss indistinguishable from a normal Material Plane (alterable morphic trait) in that the plane can be changed by spells and physical effort.
 Mixed Elemental and Energy Traits: This trait varies widely from layer to layer. In the Abyss as a whole, no one element or energy constantly dominates, though certain layers have a dominant element or energy, or a mixture of two or more.
 Mildly Chaos-Aligned and Mildly Evil-Aligned: Lawful characters in the Abyss suffer a –2 penalty on all Charisma-based checks, and good characters suffer the same penalty. Lawful good characters suffer a –4 penalty on all Charisma-based checks.
 Normal Magic.

ABYSSAL LINKS

The two most well-known access points to the Abyss are a gate in the Outlands from the town of Plague-Mort, and the River Styx. Both of these links provide access to the top layer of the Abyss, the plain of Infinite Portals.

ABYSSAL INHABITANTS

Called Demonholme by some, the Abyss harbors demons and is likely their ultimate source. Demons rule most known layers of the Abyss. Other evil creatures reside among the layers as well, including bebiliths, bodaks, retrievers, undead of every sort, renegade devils, twisted mortals, and worse. A class of demons called tanar'ri are the unchallenged masters of the Abyss, although the nigh-infinite variety of the plane means some areas exist beyond their reach.

Abyssal Petitioners

Those souls from the Material Plane that are not simply absorbed into the structure of the Abyss become petitioners called manes. Manes have pale white skin, cruel claws, sharp teeth, sparse hair, and white eyes. Often, maggots visibly squirm through a mane's bloated flesh. Manes that survive many years are sometimes “promoted” to lesser demon types, though they retain no memory of their former lives. Manes have the following special petitioner qualities:
Additional Immunities: Electricity, poison.
Resistances: Fire 20, acid 20.
Other Special Qualities: Acidic vapor, no planar commitment.
Acidic Vapor (Su): When a mane is slain, it discorporates into a cloud of noxious vapor. Anyone within 10 feet of a slain mane who fails a Reflex save (DC 20) takes 1d6 points of acid damage.
No Planar Commitment (Ex): Unlike most other petitioners, manes can leave the plane they call home.

MOVEMENT AND COMBAT

In general, the Abyss functions like the Material plane with regard to movement and combat. On layers where the environment is radically strange, different rules apply. Individual layers of the Abyss could have the firedominant trait, for example, or have subjective directional gravity. Unless stated otherwise, those traits function the same in the Abyss as they do everywhere else.

THE SHIPS OF CHAOS

Demons sometimes move from plane to plane in entropic vessels formed of powdered bones, crushed spirits, and petitioners. Meant for use against devils in the Blood War, these ships of chaos have wild powers specifically designed to counter the effects of law. The tanar'ri have commissioned only a very few ships of chaos, but the few demon-crewed ships that do sail the planes are a terror to behold. For brave or foolhardy travelers, the tanar'ri sell passage on a ship of chaos, if the price is right.

abyss mapFEATURES OF THE ABYSS

The Abyss has more layers than anyone knows, mortal or deity. A few of the most well known are described below. Vision in the Abyss is normal except on layers where environmental conditions inhibit it. Unless noted otherwise, hellish suns, phantom glows, or similarly unpleasant radiances illuminate all layers of the Abyss. Unless a particular layer somehow inhibits sound, hearing is also normal in the Abyss.

Plain of Infinite Portals

This is the topmost of the uncountable Abyssal layers. It is a barren, dusty place without life or greenery, baking beneath a hell-red sun. The dusty plains are broken by three features: huge pits in the earth, great iron strongholds, and the River Styx. The pits of this first layer are portals to deeper layers. Dropping down a given pit soon deposits the traveler into the associated layer, though jumping into random pits that lead to unknown planes of the Abyss is insanely dangerous. Most of the pits are two-way portals, but some are only one-way, leaving travelers stranded on the new layer.

RANDOM ABYSSAL LAYERS

What if your characters wind up being sent to the Abyss as a result of an adventure gone wrong? Or what if they flee powerful demons on the Plain of Infinite Portals by jumping down the nearest pit? Use the following table to randomly determine the general terrain type of an unknown layer. If desired, roll twice (or more) and combine the results.
d% Type of Layer
01–05 Air-dominant
06–10 Blood War battleground (demons against devils)
11–15 Burning hellscape
16–20 Demonic city
21–25 Desert of sand, ice, salt, or ash
26–30 Earth-dominant
31–35 Fire-dominant
36–40 Grass plain (filled with predators)
41–45 Mixed elemental-dominant (as Limbo)
46–50 Mountainous
51–55 Negative-dominant (minor or major)
56–60 Normal (as the Material Plane)
61–65 Ocean of water
66–70 Realm of powerful Abyssal entity
71–75 Sea of acid
76–80 Sea of insects
81–85 Sea of magma
86–90 Subterranean
91–95 Undead realm
96–100 Water-dominant

Iron strongholds here most often house powerful demons and their court. Such fortresses often serve as a rallying point for demonic armies on their way to join the endless Blood War. Some of that war's greatest battles take plane in this layer, deeper layers, and nearby Outer Planes. The River Styx flows a winding course on this layer. Some channels pour into the pits, while other pits well up with foul water, serving as tributaries of the mighty river. A character entering a new, unknown layer of the Abyss via a pit (or another method) can wind up in almost any sort of terrain. Develop this layer of the Abyss yourself, or use the Random Abyssal Layers sidebar to provide guidance.
Broken Reach: Red Shroud, a succubus sorcerer, rules the town of Broken Reach, which serves as a gathering point for Blood War mercenaries, a way spot for travelers insane enough to explore the Abyss, and a place for trade. The town is a set of crumbling towers surrounded by outworks of trenches, walls, and spiky barricades. Several important precincts are underground. The portal to Plague-Mort, a town in the Outlands, is beneath the main hall, for example. The food stores, the arsenal, the interrogation halls, and the crypts are likewise underground, connected by narrow tunnels. Rooms for visiting mercenaries and merchants are above ground, off the main towered hall. The inhabitants are a mix of petitioner slaves, demons of all types, and mercenaries from the Material Plane and beyond.
Ferrug: An abandoned iron stronghold is situated near the Lakes of Molten Iron, a series of natural whitehot crucibles filled with molten iron. Ferrug's former demonic lord was slain as she lay senseless while astrally traveling to the Material Plane to corrupt mortal hearts. Since then, Ferrug has hosted countless armies of demons interested in gathering workable iron to build other iron strongholds. Because the demons highly value iron, devil strike forces often attack the Lakes of Molten Iron, so Ferrug currently serves as a command center for a force of demons charged by Demogorgon to protect the lakes.

Azzagrat

Azzagrat is the realm of Graz'zt, an Abyssal lord. Azzagrat stretches over three layers, the 45th, 46th, and 47th. Because all three layers are ruled by the same Abyssal lord, they share many traits and have many portals connecting them. One of the common threads among the three layers is the River of Salt, a sparkling crystalline mass of liquid salt crystal. Needless to say, submersion in the river is deadly. Other features include portals between the three layers that appear as groves of viper trees and ovens of green fire. But given Graz'zt's cruel sense of humor, some green-fire ovens are simply full of fire and don't contain portals at all. The environments of the three realms are not terribly dangerous; each resembles a twisted version of the Material Plane. For instance, the 45th layer is like a constantly gray, rainswept steppe. The 46th layer is illuminated from the ground, so that shadows are strange and rise like columns of darkness into the sky. The 47th layer (only reachable from the previous two layers, never from the Plain of Infinite Portals) is lighted by a blue sun. Here flames are purple instead of red, and they deal cold damage. Thus, creatures normally immune to fire might be surprised when they approach the flames.

Zelatar: The largest city of Graz'zt's realm, Zelatar exists in all three layers. Doorways may allow exit onto a street or into a building, but the building interior or the street could very well exist on a different layer of the Abyss. The inhabitants of Zelatar (demons, half-fiends, tieflings, and others who revere Graz'zt) soon learn the ways of the shifting portals, but most visitors require a guide to get from place to place within the city. The Argent Palace is visible from anywhere in Zelatar, regardless of which layer the observer is looking from. The Argent Palace is Graz'zt's abode of sixtysix ivory towers and one hundred cold, mirrored halls. The palace is a sterile, echoing space where those seeking Graz'zt's audience room must wend their way through the mirror and portal maze in which ravenous bodaks roam.

Thanatos

Thanatos is the 113th layer of the Abyss. It is a cold layer of ice, thin air, and dreary moonlit sky. The layer belongs as much to the undead as to the tanar'ri—in fact, the layer has the minor negative-dominant trait. Still, fiendish mosses and fungi grow on the edges of crusty tundra. Tombstones of every imaginable and unimaginable type dot the frozen landscape, sometimes standing alone and sometimes grouped haphazardly as if in a small cemetery. Undead range everywhere.

Naratyr: Nararyr, called the City of the Dead, is a cold realm carved into the surface of a frozen ocean. Naratyr's icy architecture is a frigid necropolis of tall mausoleums, towering funeral obelisks, crypt parapets, and carpets woven of hair removed from the thousands of unquiet dead that reside in Naratyr. The city's warlike legions include retrievers, vampiric giants, and liches of all varieties. The rank and file of the population is mostly zombies, ghouls, wights, and other decaying corpses that move with a dark purpose. Who rules Naratyr? A good question. For time out of mind, a powerful demon lord named Orcus claimed the entire layer. However, Orcus was recently declared dead. A drow deity of vengeance and undeath claimed the victor's spoils and assumed control of the layer and its crowning jewel, Naratyr. But now there are strong clues that Orcus is not quite as dead as many had thought. The drow deity has disappeared, and no one knows whether she fled or was slain. Could it be that Orcus once again rules icy Thanatos, one bony hand clutching his terrible rod?

Other Abyssal layers

No tome could hope to catalogue the innumerable Abyssal layers. However, a few interesting layers are described below. Other realms controlled by the many demon princes also abide in the Abyss. Intrepid explorers who care little for their lives may discover them.
Realm of a Million Eyes: The 6th layer of the Abyss is home to the Great Mother, whom beholders revere. The realm is a network of countless twisting tunnels, and living eyes stud the tunnel walls like encrusted gems. In fact, each eye on the wall is an eye of the Great Mother.
Beholders and beholderkin of particular piety roam the eye-studded tunnels, preying on one another as well as any demons or other visitors who might accidentally fall from the Plain of Infinite Portals.

Ice Wastes: The 23rd layer of the Abyss is a bitterly cold plane of miles-deep ice, devoid of most life. A distant sun no brighter than the Material Plane's moon lights this plane. The Ice Wastes are the province of frost giants who serve Kostchtchie, their demon prince. Frost giant mages dwell with their prince in the Glacier Citadel, a fortress carved into the creaking ice between two towering peaks. Spring never comes to the Ice Wastes, and most of its inhabitants live in underground strongholds or caverns.

Demonweb Pits: The 66th layer of the Abyss is home to Lolth, the Spider Queen. The plane folds in upon itself so that it resembles a great web. A dizzying array of web tunnels interconnect with fractal complexity. Each strand is strung with portals onto the planes where Lolth is worshiped. Lolth's palace is said to be a mobile iron stronghold shaped like a spider, perpetually crawling across her planar web.

Smargard: The 74th layer is home to Merrshaulk, the yuan-ti deity. It is a realm of ever-shifting colors, moist jungles, acid rain, and fermenting poisons. There may be no jungle floor at all, just layer after layer of darker and dimmer forest canopies.

Abysm: The 88th layer of the Abyss, called the Brine Flats, is home to Demogorgon, one of the most powerful demon princes. It is a realm of briny water and rocky prominences used as rookeries by flying demons. Aboleths, kraken, and demonic manta rays war in the depths, but all bow before Demogorgon's might. Here, Demogorgon has his terrible palace, called Abysm. The portion of Abysm above water takes the form of two serpentine towers, each crowned by skull-like minarets. Here, Demogorgon wields his arcane might, attempting to induce the very Abyss to vomit forth its secrets. The bulk of his palace extends deep underwater, in chill and darkened caverns that have never seen light. The demon prince hoards his strength, only rarely involving himself directly in the Blood War. His designs go far deeper.

Slime Pits: The 222nd layer is home to both Juiblex, the Slime Lord, and Zuggtmoy, the Lady of Fungi. The layer is a bubbling morass of oozing, fetid sludge called the Amoebic Sea. Vast expanses of caustic slime engender strange life forms, sometimes by the will of the demons who reside here, but sometimes spontaneously.

Fortress of Indifference: The 348th layer is a lonely, blasted plain of tumbled rocks, jagged pinnacles, and sinister gorges devoid of natural life. Crimson clouds scrub scrub the sky, and freezing winds lash a traveler's eyes and skin. Here stands the Fortress of Indifference, a single 200-foot-tall tower of black iron gridwork. Humanoids of every variety are woven into the metal itself, used as a ghastly mortar. Most of the forms are dead, but many are undead and constantly wail and claw at the air. The Fortress houses outcast demons, half-fiends, and tieflings. Though these creatures are evil through and through, they have turned their backs on the Blood War. A nalfeshnee demon named Tapheon rules the Fortress. Tapheon's form is horribly scarred, and he constantly wears a body-brace of rusty iron that keeps his bloated form upright with long hooks. Tapheon's favorite toy is a magic rod called the Despoiler of Flesh, fashioned from sewn-together tongues. With it, the nalfeshnee can alter any creature's shape to any other shape the imagination can provide. Of course, the imagination of a demon is a foul thing, and the rod brings the ghastliest things to life.

Noisome Vale: The 489th layer of the Abyss was once ruled by a powerful balor called Tarnhem, though he has gone missing. The layer's atmosphere is a haze of acidic gas constantly regenerated by volcanic vents that scar an utterly blasted landscape. A ravine cuts through the landscape of the Noisome Vale, but it is not filled with water or even condensed acid. Instead, it channels a flood of slick, writhing worms that vary in length between 1 inch and 10 feet. These worms inhale the sulfur fumes endemic to the layer and exhale breathable air. The worms' respiration affects both shores of the river to a distance of 50 feet on either side, effectively scrubbing the air free of sulfur gas. Tarnhem's manor is built along the ravine. Thanks to the worms, it possesses a breathable atmosphere, though the constant susurrus of the writhing worms below is maddening. Tarnhem's demonic staff still maintains the manor despite the absence of Tarnhem himself (the staff believes he is imprisoned offplane). Despite Tarnhem's disappearance, the demons that guard the manor still take a dim view of unannounced visitors.

Abyssal Encounters

Use Table 7–6: Abyssal Encounters for random encounters
in the Abyss.

THE RETURN OF ORCUS

It is not clear how, or why, but the truth can no longer be denied. Orcus is back. With a vengeance. Was the demon lord really ever dead? Probably, which accounts for his long absence, and explains his recent incarnation as a power of undeath calling himself Tenebrous. As Tenebrous, Orcus was able to slay even deities, wielding an ancient power known as the Last Word. He bullied some, and slew others who stood in his way. Orcus revitalized his wand, and with its strength initiated a spell of resurrection cast by one of his last faithful servants, the half-ogre Quah-Namog. Heroes from the Material Plane seemingly disrupted this ceremony at the eleventh hour, but Orcus returned all the same. Despite the fact that the power of the Last Word is dissipated, Orcus is a cruel, heartless, and powerful demon lord in his own right. Naratyr, and the Abyssal layer of Thanatos on which it resides, is rightfully his, and he will have it no matter what. Let his enemies despair.