Layers of the Abyss

The term layer of the Abyss referred to each of the ever-changing miniature worlds in the chaotic tangle that constituted the Abyss.

The total number of Abyssal layers was not fixed at any given time, due to the ever-expanding and corrupting nature of the plane. If left unchecked, the continued presence of demons in a world in the Prime Material plane could erode the barriers between that place and the Abyss, leading to the opening of one or more portals and an ever-growing demonic presence. Over time, the Abyssal influence and the long-term presence of one or more demon lords could permanently corrupt that entire world, effectively converting it into a new layer.

Nevertheless, numerous attempts were made to catalog the layers. Some sources placed the number of layers at 666, while the Fraternity of Order claimed to have cataloged at least 679 layers, of which 141 were considered habitable. Most were accessible via portals from Pazunia, or from the Grand Abyss, but many had been sealed away and were no longer accessible. Those were called the "Lost Planes of the Abyss".

"No matter where you go in the Abyss, at least you have the comfort of knowing that there's surely a layer that's even worse."

- Addean, a tiefling merchant

Cosmography
The Fraternity of Order numbered the layers by order of discovery. For that reason, there was not necessarily a spatial relation between layers of consecutive numbers, or a correlation with depth. Rather, a layer was considered "deep" if it lacked a direct connection with the first layer.

Each Abyssal layer was unique. The only common feature of all layers was their harsh and inhospitable environment, as well as the apparent corroded and decaying state of every feature, a reflection of the entropic nature of the entire plane. Some layers were controlled by one or more demon lords, whose natures ended up defining the character of the layer under their domain. Deities who claimed divine realms in the Abyss and even demon lords were extremely territorial and intolerant of intruders, always making an effort to extend their dominion over their entire layers. For that reason, each layer typically contained a single realm, so it was equivalent to either refer to a particular layer or to the realm therein.

Layer 1: Plain of Infinite Portals
Also known as Pazunia, the Palace of 1,001 Closets, the Plain of a Thousand Portals, and the Plain of Yawning Pits, this layer was a barren wasteland of scorching winds under a relentless red sun. The surface was marked by massive dark pits: portals that plunged into many, but not all, of the deeper layers. The surface of the layer, cut through by the river Styx, connected to both Pandemonium and Hades in different edges. Its air space was ruled by the obyrith Pazuzu, Prince of the Lower Aerial Kingdoms. The landscape was marked with scattered iron fortresses claimed as fiefs by other demon lords, such as Aldinach, the Lady of Change, and Baltazo, a retired general of the Blood War, who claimed smaller domains on the layer as their own.

The layer was home to countless mane petitioners, who were constantly hunted for food or thrust down the pits into the deeper layers, as well as gangs of molydei that hunted demon stragglers. There were also a large number of mortal and outsider merchants and visitors throughout the layer, attracted by the opportunities offered by the layer's countless portals. The largest of these pits was known as the Grand Abyss, which was considered a layer in its own right. Some pits worked as two-way portals, but others were only one-way.

Layer 2: Driller's Hives
Realm of Tharzax, the Chattering Prince, demon lord of poison. It was inhabited by ekolids and hives of enormous insects at constant war with each other. The environment slowly turned visitors into insect creatures, although paladins were immune to this effect.

Layer 3: The Forgotten Land
This layer drained the memories and identities of any mortal or demon that set foot on it. It was the realm of the demon lord Zzyczesiya,, the Ungrasped. The layer itself was said to have originated by a failed attempt to subvert the flow of the river Styx.

The layer was dotted with ancient abandoned cities. It was inhabited by creatures that fed on the life force of victims or on the loose thoughts that permeated the environment, such as reason stealers and vasuthants. It was also rumored to contain fragments of the Rod of Seven Parts or the Barbatos device; for this reason, demon lords such as Graz'zt and Demogorgon often sent exploration parties to the layer, led by golems.

Layer 4: The Grand Abyss
Also known as the Blood Rift, this layer was a bottomless chasm that started from Pazunia and reached almost every single layer of the Abyss via portals or gates. The layer itself had no ruler.

In the World Axis cosmology, the tower of Khin-Oin was located in the Blood Rift. It was an enormous tower that rose  above the city of Morglon-Daar on Pazunia and whose majority was anchored to the walls of the layer. It was the realm of Phraxas.

The origin of the layer was a subject of debate among sages: some sources claimed that the layer originated from the explorations of the obyriths, who cooperated in exploring and perusing the various portals along the walls of the cliff. Others, however, claimed that the rift originated as a catastrophic effect of the battle between Demogorgon and Obox-ob, and appeared as a scar that permeated the very fabric of the plane. In any case, maps to the various portals along the crevasse were nearly all inaccurate, due to the ever-changing nature of the plane.

The realm contained ancient constructions along its depths, such as towers and bridges, that connected portals that were located in similar heights. These bridges were guarded by a wandering klurichir. The walls of the canyon were bathed by the toxic Blood River, whose exact course was also ever-changing, and the red mist that rose from the river favored the growth of moss and lichen along the walls. The rift was a constant battleground of demons, and plummeting corpses were not an uncommon sight.

Layer 5: Wormblood
Lordship over this layer was contested. A tributary of the river Styx reached this layer. The environment infected all visitors with a disease similar to mummy rot that destroyed their bodies from the inside out within a year. The disease bypassed known magical protection.

Layer 6: Realm of a Million Eyes
Realm of the Great Mother, chief goddess of the beholder pantheon. It was inhabited by every kind of beholder and beholderkin, who constantly fought each other.

The layer was a twisting network of tunnels filled with eyes protruding from the walls. The eyes belonged to the Great Mother herself.

Layer 7: The Phantom Plane
Also known as Kearackinin. All portals leading to this layer were sealed. It was the realm of the demon lord Sess'innek, the Emperor Lizard, worshiped by lizardfolk. The layer was inhabited by lizard kings. It was discovered by Mordenkainen.

Layer 8: The Skin-Shedder
Realm of the demon lord Volisupula, the Flensed Marquesse. The layer corrupted the souls of all visitors in a matter of days. The only immune creatures to this effect were tieflings.

Layer 9: Burningwater
This layer had no ruler. It was an ocean of acid, inhabited by twisted sea creatures.

Layer 10: That Hellhole
This layer had no ruler. The only food available in the layer were sentient creatures. It was discovered by the dwarf Gorbin, who spent only three minutes in the layer, but returned with numerous bite and puncture marks in his adamantine armor.

Layer 11: Molrat
Lordship over this layer was contested. It was an underground land of tunnels in eternal darkness, inhabited by demons that constantly hunted each other by sense of smell.

Layer 12: Twelvetrees
This layer had no ruler. It was considered a pilgrimage site for demons and was respected by all demon lords.

The layer had been the site of a vile arcane ritual that involved the sacrifice of twelve astral devas who had been tricked into going to the plane for a peace conference. The devas were bound to twelve enormous pine trees around an altar in the otherwise desolate layer, and the ritual infused the entire plane with strong evil energy that amplified the effects of all evil magic performed there. The deafening screams of the devas could still be heard throughout the layer, under a permanently cloudy and thunderous sky.

Besides the inflow of low-ranking demon pilgrims who enjoyed a sort of religious ecstasy when visiting, the layer was sparsely inhabited by patrolling chasmes and kelvezus. A detachment of mortal sages from the Doomguard held a fortress on the layer, near a two-way portal to Pazunia. Those sages held an alliance with a consortium of demons to build ships of chaos.

Layer 13: Blood Tor
This layer contained a vast ocean of red waters. It was characterized by inflicting bad luck on its visitors. It was the realm of two deities: Beshaba, the Maid of Misfortune; and Umberlee, the Bitch Queen, who dwelt in the depths of the red ocean.

The layer had been the site of an invasion of the Abyss by baatezu, who counted it as one of their greatest successes in the early days of the Blood War.

Layer 14: The Steaming Fen
This layer was the realm of the Queen of Chaos. It was a vast foul briny ocean from which a mountain so vast as to dwarf any mountain in the Prime Material Plane rose. The queen ruled over the layer from a gigantic castle carved within this mountain, a labyrinth of tunnels and passages with no clear way out. The throne room itself was an enormous cavern containing a pool of salt water covered with a layer of oil in perpetual flames.

Layer 17: Death's Reward
Realm of the demon lord Abraxas the Unfathomable.

Layer 21: The Sixth Pyre
Realm of the demon lord Kardum, Lord of the Balors.

Layer 23: The Iron Wastes
Also known as the Ice Wastes, this icy layer was a vast expanse of glaciers, mountains, and ruins buried in miles-deep ice, constantly battered by an extremely cold and violent blizzard and illuminated by a dim and distant source, similar in brightness to a moon. It was the realm of the demon lord Kostchtchie, the Prince of Wrath.

The layer held an enormous amount of portals leading to a variety of planes, as well as other Abyssal layers. It was inhabited by frost giants, winter wolves, mavawhans, a small colony of ice archons, and several desperate demons. Because of the bitter cold, its inhabitants dwelt mostly in caves.

The plane was also the site of the ancient demon lord Veshvoriak's imprisonment. He was said to possess a profound knowledge of various subjects, available for a price.

Layer 27: Malignebula
This layer was an endless expanse of acid clouds with no solid ground. It was the realm of the Gaseous Lady Lissa'aere the Noxious. The swirling poisonous mists were also home to alu-fiends, nabassu, and vrocks who formed an army of the Gaseous Lady to defend her realm from trespassers or direct baatezu threats to the borders of the Abyss.

Some of the acidic clouds could harden into ice occasionally, but would melt after fiends perched on them to rest. It was believed that those who fell far too deep were consumed by Lissa'aere herself.

Layer 32: Sholo-Tovoth: The Fields of Consumption
This layer was dominated by pure all-consuming hunger. Random pits spontaneously opened on the ground, dropping creatures in slowly digesting pools; the layer even affected visitors, who started losing taste for food and developed cravings for the flesh of sentient beings. It was mostly surrounded by the Gnashing Crags, a range of mountains that resembled teeth. A second range of similar-looking but upside-down mountains could sometimes be glimpsed from far above the clouds. It was the realm of the demon prince Turaglas, the Ebon Maw.

The layer was inhabited by predatory insects, purple worms, vrocks, and other predators. Forests of flesh-eating trees led to an enormous acid ocean of gastric juices that eventually drained into the river Styx. At the bottom of this ocean, Turaglas slept, slowly coming back to consciousness.

Layers 45–47: Azzagrat


Also called the Triple realm, Azzagrat spanned the 45th, 46th, and 47th layers of the Abyss:
 * Rauwend : The 45th layer was a windswept steppe with a continual gray sky.
 * Shadowsky : The 46th layer had a luminous ground that projected shadows upwards into the sky.
 * Voorz'zt : The 47th layer could only be accessed from the previous two; it received light from a blue sun and had purple icy flames.

All three layers were connected by the River of Salt. Rocks from Rauwend and Voorz'zt could be used to produce the purple bathaerel powder, a powerful rust-removing substance.

The largest city of the Triple Realm was Zelatar, which was also the location of the Argent Palace, Graz'zt's seat of power. It existed on all three layers and attracted visitors in search of obscure magic knowledge.

Layer 48: Skeiqulac, the Ocean of Tears
Also known as Nerebdian Vast, this layer was a desert realm that bordered both Azzagrat and Shaddonon. It had no ruler, but was coveted by Graz'zt, who wanted to make it his fourth kingdom.

Layer 49: Shaddonon
Realm of the demon lady Rhyxali, Queen of shadow demons.

Layer 52: Vorganund
Lordship over this layer was contested.

Layer 53: Phage Breeding Grounds
Realm of Urae-Naas the Slaad Lord. It resembled the interior of an endless mass of decaying intestines. The entire layer itself was said to be the corpse of the dead primordial Ramenos, god of the bullywugs.

Layer 57: Torturous Truth
Realm of the demon lord Alvarez, the Purging Duke.

Layer 65: Court of the Spider Queen
This layer was also under the domain of Lolth.

Layer 66: The Demonweb Pits
This layer was an immense network of webs that folded on themselves to form a single giant spider web. All structures such as buildings and ships hung from the webs as if caught by them. The web created random portals connecting to the Prime Material Plane that drew in objects. Deep within the web were dungeons, and far beneath those lay the bottomless pits where Lolth dwelt.

Layer 67: The Heaving Hills
Realm of varrangoin. It was formed of mountainous and swampy terrain and constantly shaken by earthquakes. With each earthquake, the terrain types were inverted and sometimes old ruins were unearthed. It was inhabited by froghemoths and hezrou.

Layer 68: The Swallowed Void
This layer was abandoned. It was barren and completely airless.

Layer 69: Gibbering Hollow
Also known as The Crushing Plain. This layer spawned an unusually high amount of manes. The creatures were densely packed and occupied every bit of space on the layer's surface and underground tunnels, potentially crushing and suffocating any creature who arrived by means of a portal. The layer had been unclaimed until the primordial Ollomegh arrived, claiming the layer as his domain and starting to endlessly devour the manes to satiate his equally endless appetite.

Layer 70: The Ice Floe
This layer had no ruler. It was a cold plain of thin ice over an ocean of black water with intense undercurrents. The ice could break easily under heavy weight. The cold drained away the life force of all creatures. It was discovered by githzerai.

Layer 71: Spirac
This layer was a perpetual wilderness that resisted any attempt at civilization. Its dense fern forests and weeds quickly consumed any buildings until not even their ruins remained. For that reason, the layer had no ruler and served as hunting grounds for demon lords seeking game such as yeth hounds, vorrs, and nightmare beasts.

Atop one of the central mountains of the layer, there was a pool that had the power to rejuvenate a mortal that bathed in it. The price was to surrender a part of one's free will to Soneillon, a demon lady who dwelt in the depths of the pool.

Layer 72: Darklight
Realm of the demon lord Nocticula the Undeniable. Within the layer, the shadows of good creatures shone brightly, while evil creatures were shrouded in darkness. The bright creatures were easily hunted down by demons to be sold as slaves or killed.

Layer 73: The Wells of Darkness
This layer was a rocky plain illuminated by a dim blue sun. It had scattered elevations surrounding pools of a black liquid, connected with one another by marble walkways. At the top of a higher mound, the crumbling fortress of Overlook, inhabited by specters and wraiths, provided a good view of the entire layer.

The realm had no ruler and was used by demon lords as a prison. The black liquid of the pools prevented escape, but allowed some telepathic communication so that the large custodian bodaks knew that the prisoners were still present. Only four prisoners were known to have escaped: Bayemon, Shaktari, Siragle, and Zzyczesiya.

One particular prisoner was the demon lady Shami-Amourae, the Lady of Delights and former consort of Demogorgon, said to be one of the very few who truly understood his double personality. Shami-Amourae remained imprisoned until an attempted escape. She was later presumed dead, and was found to have become a vestige trapped within the domain of Barovia in the Shadowfell.

Layer 74: Smaragd
This layer was an extremely hot jungle of several layers of emerald canopies of shifting colors and poisonous fermenting pools under constant acid rain. It contained the realms of Merrshaulk, god of the yuan-ti, and Ramenos, god of the bullywugs, as well as the Viper Pit, realm of Sseth.

Layer 77: The Gates of Heaven
Realm of the demon lords Munkir, the White Guardian, and Nekir, the Black Guardian.

Layer 79: The Emessu Tunnels
Realm of the demon lord Anarazel, the Daring Darkness.

Layer 81: Blood Shallows
This layer was a marsh of acidic blood-red water under a white sky with blue clouds. The river Styx ran on the edge of the swamp. The layer had no ruler, and the few patches of high ground available were claimed by different demons and obyriths. It had been the former realm of Obox-ob before he was forced to retreat to Zionyn by the Queen of Chaos.

Layer 88: Gaping Maw


This layer consisted of a vast continent covered in jungle surrounded by an endless ocean and brine flats. It was the realm of the demon lord Demogorgon, the Prince of Demons, the oldest and highest-ranking demon in the Abyss.

The jungle portion of the realm, known as the Screaming Jungle, was inhabited by troglodytes, lizardfolk, hezrou, yuan-ti, dinosaurs, dire apes, and barlguras. It held a two-way portal connecting to the Guttering Grove. Together with Slugbed and Shedaklah, this was one of the layers whose jungles were inhabited by threeb, a type of leech that was the main ingredient of the Quelaerel sauce.

The ocean portion was inhabited by aboleths, ixitxachitl, and krakens. Demogorgon's lair was in the palace of Abysm: two serpentine towers topped with skull-shaped minarets whose bulk extended deep underwater into dark caverns. The deepest of these caverns and the deepest trenches of the ocean were connected with the Shadowsea.

The entire layer was sometimes referred to by the names of its most prominent features, such as Abysm and Brine Flats.

Layer 89: The Shadowsea
This layer was a deep and perpetually dark ocean. It was the realm of the obyrith Dagon, Prince of the Darkened Depths, who ruled it from inside an amorphous slimy palace inhabited by giant sea worms and luminescent gliding creatures. The realm was connected to the deepest trenches of Gaping Maw.

The layer was inhabited mostly by wastriliths, who had free rein of the depths, as well as roaming gigantic half-alive shapeless clouds of discolored pollution that stripped the flesh from anything that entered them.

Layer 90: The Guttering Grove
This layer was the realm of the demon lord Ilsidahur, the Howling King, patron of the barlgura and ally of Demogorgon. It held a two-way portal to the Screaming Jungle, a location in Gaping Maw.

Demogorgon and Ilsidahur once managed to capture the eladrin paragon Gwynharwyf, but, due to their constant bickering, she was rescued and escaped, causing a strain in the demons' relations and fear by Ilsidahur of an invasion of his realm by Demogorgon. In fact, some later sources did call this layer the Screaming Jungle, since Demogorgon extended his domain to the layer and effectively merged it with his existing realm.

Layer 92: Ulgurshek
Realm of Ulgurshek, who was not a demon lord but a far more ancient entity who had been created even before the Great Wheel was formed.

Layer 99: Unnamed
This layer had no ruler. It consisted of a series of interconnected realms of completely different characteristics.

Layer 100: The Barrens
Realm of Oublivae. This layer was an enormous expanse containing ruins of all past and future civilizations. It was believed that the Barrens had been an astral domain that had fallen in the Abyss.

Layer 111: The Mind of Evil
Realm of the demon lord Sch'thrruppasstt (sometimes known as Sch'theraqpasstt), the Serpent Reborn,  believed by some to be the creator of the yuan-ti race. The layer was a sentient but insane chaotic whirling. It was put in that state when Sch'thrruppasstt attempted to merge his life essence with the plane in an attempt to gain ultimate power and immortality. The process succeeded, fusing the layer and its master's mind into one and making the Serpent Reborn indestructible to all but those with the ability to destroy the entire layer. However, merging with the chaotic plane ruined his sanity and the layer. He could still send out a minor fragment of his psyche that would reform in 111 days if destroyed elsewhere. Magic was nullified on the layer and anyone trapped there was at the mercy of an insane, living dimension. Most planar travelers knew of the danger of this realm and so the Mind of Evil was avoided at all costs.

Layer 113: Thanatos
This layer was a land of ruin and death, with sterile heaths, black forests, and desolate mountains filled with ruins and scattered tombs, inhabited by a variety of undead.

The demon lord Orcus, the Prince of Undeath, ruled Thanatos from his seat in the Everlost palace, a castle made of obsidian and bone located in a vast wasteland called Oblivion's End. Orcus had been temporarily deposed of his post by the drow goddess Kiaransalee, who took control of the realm for a few centuries until Orcus returned and deposed her, forcing her to flee to the Demonweb.

Orcus maintained a second lair in the fortress city of Naratyr, the City of the Dead. It was a quiet, cold and mostly empty city (except for the occasional wandering undead) surrounded by an icy moat fed by the river Styx. The city used to be Kiaransalee's winter capital, and was left deserted following the return of the layer's original master. The inner walls of the central castle of bone were made of flesh and decorated with carpets made of hair.

Some sources counted this as layer 333.

Layer 128: Slugbed
This layer was a vast expanse of forests, shallow seas, and underground caverns, always covered in fog under a faintly lit sky. It was the realm of the demon lord Lupercio, the Baron of Sloth, who slept most of the time in a dung-filled area covered in utter darkness. It was inhabited by shadow demons and fiendish gastropods.

On rare occasions, the sun did shine feebly through the fog on the layer, revealing glimpses of majestic angelic castles on cloud tops, a possible attempt by the angels to take advantage of Lupercio's slumber in order to convert the layer into a bastion of good.

Together with Gaping Maw and Shedaklah, this was one of the layers whose jungles were inhabited by threeb, a type of leech that was the main ingredient of the Quelaerel sauce.

Layer 137: Outcasts' End
Realm of the exiled outcast devil Azazel, Prince of Scapegoats.

Layer 142: Lifebane
Realm of Chemosh, god of the undead.

Layer 148: Torrent
Lordship over this layer was contested.

Layer 176: Hollow's Heart
This layer contained the realm of the demon lord Fraz-Urb'luu, the Prince of Deception and demon lord of illusions.

Fraz-Urb'luu's realm used to cover the entire layer, until the demon prince was imprisoned for over two centuries in the world of Oerth. Upon his return, he found the layer to have been destabilized, becoming little more than a featureless flat expanse of white dust under a starless black sky with very few structures scattered on it. Within a few decades of his return he had managed to rebuild part of his realm but, despite having accomplished recreating much of what existed, up to the size of a large continent, the demon lord required a legendary staff of power in order to rebuild the realm in its entirety. Without the aid of the staff, progress was slow and by the late 1480s DR most of the infinite plain remained nearly entirely featureless.

The demon lord's lair was located at the center of the continent-sized reconstructed area, in the city of Zoragmelok, a circular walled city of adamantine walls and impossible architecture.

Layer 177: Writhing Realm
Realm of the obyrith Ugudenk the Squirming King.

Layer 181: The Rotting Plain
This layer was the realm of Laogzed, patron god of troglodytes. The layer was dominated by a constant nauseating stench throughout vast baking hot savannas and shallow swamps. Laogzed's personal lair was a cavern complex he constantly prowled searching for things to devour. Whatever he devoured would become one with the plane itself, and so the plains were used by other tanar'ri as a permanent dumping ground.

Layer 191: Fountain of Screams
This layer had no ruler.

Layer 193: Vulgarea
Realm of Eshebala, goddess of foxwomen and wolfweres.

Layer 222: Shedaklah
Also known as The Slime Pits, it was the realm of Juiblex, Demon Prince of Slimes, and Zuggtmoy, Demon Queen of Fungi.

The realm was a bubbling fetid swamp, covered with oozes, molds and slimes that formed strange organic shapes, under a mud-brown sky overcast with green clouds from which torrential rains of filth fell every few hours. Zuggmoy's palace on the plane consisted of dozens of gigantic yellow and brown mushrooms, connected by bridges of shelf-fungi and surrounded by poisonous vapors and acidic puffballs.

Together with Gaping Maw and the Slugbed, this was one of the layers whose jungles were inhabited by threeb, a type of leech that was the main ingredient of the Quelaerel sauce.

Layer 223: Offalmound
Lordship over this layer, sometimes known as Rarandreth, was contested. It was once the realm of Moander, the Rotting God, before he was slain by Finder Wyvernspur.

Layer 230: The Dreaming Gulf
This layer had no ruler. It was a dark, windy, and phantasmagoric realm that contained floating dreams of evil gods of dead pantheons. These dreams were then slowly processed by the Abyss itself and then released on the Prime Material Plane in the form of loumara demons.

Layer 241: Palpitatia
This devastated layer was eternally dark and inhabited by specters and shadows. It was the realm of the bugbear deities Skiggaret and Grankhul.

Layer 245: The Scalding Sea
Lordship over this layer was contested. It was a vast ocean of acid. A black glass island stood in the ocean, containing the ruins of a small town whose walls had been encrusted with its former inhabitants, frozen in their last agonizing screams. In the center of town stood the Fountain of Screams, that kept continuously spraying potent acid. The layer was inhabited by babau, dretches, succubi, and vrocks.

Layer 248: The Hidden Layer
This layer was constantly ravaged by lightning storms, torrential rain, and strong winds. It had vast forests of deadly plant life such as assassin vines, bloodthorns, ironmaws, and viper trees. It was the realm of Eltab, Lord of the Hidden Layer, until he was bound to the Prime Material Plane in.

During Eltab's absence, his balor lieutenants fought constantly for control of the layer. As a consequence of Eltab's summoning and imprisonment, fragments of the layer called demoncysts were transported to Northeastern Faerûn, where they lay buried and many remained undiscovered.

Layer 274: Durao
This layer had no ruler. It was a militaristic layer with iron roads and vast fetid swamps, with military encampments and barracks assembled on the shores of the river Styx. Most of the Tanar'ri armies departed to wage the Blood War in Gehenna from this layer. Three molydei patrolled the outskirts of the plane, looking for deserters and spies.

Layer 277: Belistor
An almost entirely empty void, realm of the demon lord Yrsillar, Lord of the Void.

Layer 297: The Sighing Cliffs
Realm of the demon lady Lynkhab, Lady of Regret.

Layer 300: Feng-Tu
This layer resembled a citadel on a margin of the river How Nai-ho, a branch of the river Styx. It was inhabited by manes and various types of demons. It was the realm of Tou Mu, goddess of the North Star, and Lu Yueh, god of epidemics.

Layer 303: The Sulfanorum
This layer had no ruler. It was a smoke-filled realm with countless small fire pits where demons went to relax and smoke pipes of flesh, dung, and other foul materials.

Layer 313: Gorrion's Grasp
Lordship of this layer was contested. It was the site of the balor Illssender's tower, where he had imprisoned a molydeus.

Layer 333: The Broken Scale
Realm of Hiddukel, god of lies and greed.

Layer 340: The Black Blizzard
Lordship of this layer was contested.

Layer 348: Indifference
This layer had been the realm of the demon lord Thralhavoc, who abandoned it to pursue other goals and left it with no ruler.

It was a frigid and sterile rocky plain filled with pinnacles and gorges, under a sky of red clouds and a constantly frosty air. The layer was the site of the Fortress of Indifference, also known as Taelac Mirrimbar, ruled by the nalfeshnee Tapheon.

Layer 359: The Arc of Eternity
Realm of Eldanoth the Bloodless Scion.

Layer 377: Plains of Gallenshu
This layer had no ruler. It was a plane of continuous, aimless motion and decay, in which dust blocked all sight like a constant fog over a ground of powdery flesh, bones, and blood. It was inhabited by armanites who lived in and traveled between a few scattered towns.

The layer was discovered by Xorna, a former githyanki slave of the armanites who managed to escape her captivity.

Gallenshu was once a lush land with over a dozen cities inhabited by varrangoins. A map-like painting of the layer from that time period was located in the fortress Overlook in The Wells of Darkness.

Layer 380: Hungry Tarns
This layer was a bleak domain of poisonous fens and black, bottomless lakes previously ruled by the not-quite-dead obyrith lord Sertrous. Formerly a demon lord of parasites and crawling things, Sertrous came to be associated with snakes, and the more powerful he became, the more infested his abandoned home became with golothomas and other serpentine horrors.

Layer 399: Worm Realm
This layer was entirely made of solid rock, hollowed out into a maze of tunnels and chambers. It was the realm of the gnome god Urdlen, the Crawler Below, god of greed and murder.

The layer was inhabited by gnome petitioners, manes, purple worms, hezrou, and umber hulks, who were all infected by a rotting fungal growth. This infectious disease was said to be the result of some past feud between Urdlen and Zuggtmoy.

Layer 400: Woeful Escarand
Also known as the Mountain of Woe, this was the realm of the Lords of Woe. It was said that the nalfeshnee lords of this realm seated on their flaming thrones had the power to determine whether new petitioners would be transformed into larvae, manes, dretches, or rutterkin. There were also rumors of the nalfeshnees' power to promote or demote generals in the Blood War.

Layer 403: The Rainless Waste
This layer had no ruler. It was a desert realm, filled with gigantic sulfur-spewing rifts. On the edge of one such rift lay the city of Mal Arundak, the City of Confusion, ruled by the fallen trumpet archon Alusiel.

Layer 421: The White Kingdom
Ruled by Doresain the King of Ghouls, who once had been a vassal to Orcus and later forced into subservience to Yeenoghu, but later became a free agent in full control of his realm. The White Kingdom itself was an undead aristocracy run by creatures known as true ghouls. The civilized, if flesh-loving, nobility ran a cosmopolitan society with members such as abyssal ghouls, gnolls, and hyena-like maurezhi. Ghouls faithful to Doresain sometimes attempted to recreate lesser versions of the White Kingdom in the Prime Material Plane.

Layer 422: Death Dells
Also known as Yeenoghu's Realm or the Seeping Woods, the Death Dells consisted of an endless hunting ground of barren hills and ravines, with a few structures and scattered signs of civilization. It was populated by gnolls, ghouls, and hyenas, and was ruled by Yeenoghu, the Gnoll Lord.

Layer 423: Galun-Khur
The ruler of this layer was unknown.

Layer 444: Unnamed
This layer was infested with adarus, whose corruption had turned it into a swamp of sticky mud. Petitioners sent there were tortured and dismembered for eternity.

Layer 452: Ahriman-abad
Realm of Ahrimanes, Chief of the cacodemons.

Layer 471: Androlynne
This layer was one of the least accessible in the Abyss. It was the realm of the obyrith Pale Night, the Mother of Demons, and a prison for an army of eladrin from Arborea whom Pale Night trapped there to torture and kill. However, many good-aligned individuals, such as a ki-rin, foo creatures, moon dogs, hollyphants, and couatls, invaded Androlynne to fiercely defend the captive eladrin and to attempt to free them from Pale Night.

Because of the centuries of genuinely good influence on the plane, Androlynne became a surreally beautiful and alien place, with huge purple clouds that assumed strange shapes and lush vegetation.

Layer 480: Guttlevetch
This layer was home to ceaseless hurricanes, bloody beaches, and shipwrecks beyond counting. Guttlevetch was originally the realm of the demon lord Zuregurex, Lord of the Drowned. After a failed ploy by Zuregurex to invade the Gaping Maw, Demogorgon destroyed Guttlevetch, sinking its islands and turning the layer's waters against its ruler. Zuregurex was forced to abandon Guttlevetch and flee to the Scalding Sea, but was rumored to secretly have returned to rebuild his realm.

Layer 487: Lair of the Beast and Mansion of the Rake
This layer was the interior of a vast, ever-changing baroque palace. It was the realm of the vampire demigod Kanchelsis, who enjoyed constantly changing his halls, stairways, and gardens to terrorize visitors. The mansion held regular meetings of the vampiric brotherhood known as the Union of Eclipses, composed of elder vampires from different worlds.

Layer 489: Noisome Vale
This layer was ruled by the balor Tarnhem until his imprisonment and enslavement by his son Acererak. Afterwards, lordship of the layer was contested.

It was a volcanic layer with an acidic atmosphere, cut through by a worm-infested ravine. The river of worms breathed the acidic gas and exhaled breathable air. Tarnhem's mansion was built along the ravine and remained occupied by his demonic servants who awaited his return.

Layer 493: The Steeping Isle
This layer was the realm of the demon lord Siragle the Ineffable. It was a small and repulsive place with few inhabitants and almost no resources.

Layer 499: Carroristo
This layer had no ruler. It consisted of a caustic sea with a rocky island containing the iron fortress of the same name as the plane. It was inhabited by hezrou, ixitxachitl, sea trolls, and wastriliths. The fortress had once been the site of a baatezu invasion.

Layer 500: Unnamed
Together with the Caverns of the Skull, this layer was ruled by the goddess Kali, the Black Earth Mother. It was covered in blood-red tropical vegetation and was inhabited by several demons, as well as chaotic evil rakshasas. The layer also had an ocean of blood from which sounds of screaming could be constantly heard. Numerous portals were scattered throughout the jungle and above the ocean, leading to several other layers.

Layer 503: Torremor
This layer was an enormous tangle of pieces of masonry such as bridges, arches, beams, and pinnacles, held together by ropes and chains. It had once been the realm of the demon lord Pazuzu, who imprisoned Lamashtu, the Demon Queen of Monstrous Births, in the prison of Onstrakker's Nest, a building made of bones, earth, and stone within the enormous structure. Even though she was impaled by the building's spire, Lamashtu took control of the layer and made it her realm.

Layer 507: Occipitus
This layer incorporated what had once been a part of Celestia, after it was invaded by an army of conquering demons. In order to contain the invasion, the angels detached a portion of the plane and cast it into the Abyss, where it merged with the existing layer of Occipitus. The demon lord Adimarchus, the Prince of Madness, a fallen planetar who led the invasion, took control of the piece of conquered Celestia and became lord of the entire layer. He remained so until his imprisonment in Carceri following a battle with the forces of Graz'zt.

Occipitus had an organic appearance, with the ground made of a spongy flesh-like substance; forests of bones-like columns reminiscent of massive rib-bones; and plains of ulcers and cysts sometime still digesting fallen celestials. The layer had the form of a large basin with a mountain-sized skull in its center, and deadly plasms of fire and evil energy filled its sky. The layer contained many places still infused with the power of Celestia, causing fiends to stay away from them.

After Adimarchus's disappearance, the layer remained mostly abandoned and had a reputation of being a cursed place, even for demons. Any fiend who lingered there started suffering from madness and magical illnesses, as the demon lord's madness kept leaking into the layer.

Layer 518: Melantholep
This layer inflicted madness on whoever visited it. It was said to be the nesting grounds of the chole dragons. It was not known whether "Melantholep" was the name of the layer itself or of some unknown demon prince who ruled over it.

Layer 519: March of the Pierced Men
This layer had no ruler. Similarly to the Forest of Living Tongues, it was one of many layers where souls of dead mortals were sent to be tortured.

Layer 524: Shatterstone
This layer was the realm of the ogre and troll god Vaprak the Destroyer. The deity was said to live in a pitiful cave at the base of a cliff, and was, along with his followers, despised by giants and other inhabitants of the plane.

Layer 528: Molor
This layer was also known as the Stinking Realm. It was dominated with decay, filth, and oozes, and its inhabitants carried diseases and parasites. Together with Shedaklah, this layer was one of the realms of Juiblex, the Faceless Lord, and was connected with it by several portals.

Molor was inhabited by oozes, otyughs, and civilization-shunning demons. The only known settlement in the realm was the city of Thullgrime.

Layer 531: Vudra
This layer was dominated by the Bloodsea, an ocean of poisonous blood dotted with hundreds of islands overgrown with monstrous tropical plants that only existed there. The very air was poisonous. It was the realm of the giant eight-armed marilith Shaktari, the Queen of Mariliths. While powerful mariliths ruled many of the islands, Shaktari spent most of the time at the bottom of the Bloodsea, which was connected to the river Styx.

The native creatures in the layer included rakshasa, yuan-ti, and eye-wings. The poisonous nature of the realm could be temporarily countered by drinking a naturally occurring fluid in the plane known as q'laari, or Shaktari's Ichor, which was said to taste like maple syrup.

Layer 548: Garavond
An airless void, realm of Haagenti, Demon lord of alchemy and artifice. It was one of the few layers that was not connected to the Blood Rift.

Layer 550: Forest of Living Tongues
This layer had no ruler. Similarly to the March of the Pierced Men, it was one of many layers where souls of dead mortals were sent to be tortured.

Layer 558: Fleshforges
This layer was an infinite molten mass of constantly changing flesh and protoplasm. It was the realm of Dwiergus, the Chrysalis Prince. The plane was marked by lakes of organic material and mountains of bone. Dwiergus's seat was in the Chitin Palace, which floated in the center of a swirling ocean of molten flesh.

Other demon lords created pool-like portals into the Fleshforges to fuel the creation of their own demons. Demogorgon held several such pools in the city of Lemoriax in Gaping Maw, and Baphomet had such a portal built into the Tower of Science deep within the Endless Maze.

Layer 566: Soulfreeze
This icy layer was the realm of Aseroth, the Winter Warlock, who had formerly been an elemental prince that turned into a demon. It was predominantly a permafrost layer with an advancing glacier, inhabited by remorhazes, ice archons, and different types of demons. The extremely malevolent cold of the layer was said to be capable of freezing creatures' thoughts and emotions.

There was a two-way portal connecting this realm with the para-elemental plane of ice, but activation of the portal required the destruction of a mortal soul.

Layer 570: Shendilavri
Realm of Malcanthet, queen of the succubi. Before her domain, it was a vast plane of living flesh, but Malcanthet turned it into a beautiful world of grassy hills on the shore of an ocean under perpetual sunset.

Among the carefully built white buildings throughout the hills, Malcanthet's seat of power was in the coastal city of Rivenheart, said to contain all possible pleasures and desires to tempt its visitors into relaxing. It was also home to the Radiant Sisters, Malcanthet's own personal guards and loyal lilitu bards who protected her from would-be usurpers.

Layer 586: Prison of the Mad God
A swirling vortex of wind and flying rocks, this layer was the realm of the derro demigod Diinkarazan, who had been cursed with permanent insanity and imprisoned there by Ilsensine.

Layer 597: Goranthis
Also known as the True Paradise, this infinite garden-like pleasure palace was the realm of Socothbenoth the Persuader.

The Persuader ruled his realm from atop the Palace of Quivering Flesh, from where he had full sight of the gardens of Saturnalia and the white banks of the river Styx. The brass minarets of the realm contained the demon lord's court and servants, who dwelt in endless seduction, false beauty, and deviancy.

Layer 600: Endless Maze
The realm of Baphomet, the Horned King and Prince of Beasts. It was an infinite maze inhabited by minotaurs, ogres, and goristros. The obyrith Pale Night resided in the layer and retained control over a portion of it from within the Bone Castle.

Layer 601: Conflagratum
This layer burned with a bright white flame that consumed a ruined city with strange architecture and geometry. It was the realm of Alzrius, Lord of Infernal Light, and was the native home of fire spiders.

Layer 628: Vallashan
This layer had no ruler. It was designed to allow for an apparently easy victory to conquering armies of good alignment, only to corrupt the souls of the conquerors and turn them against each other.

Layer 643: Caverns of the Skull
Together with layer 500, this layer was ruled by the lesser goddess Kali, the Black Earth Mother. It was a series of ever-changing caverns inhabited by xorn, eyewings, fetch, fireshadows, and petitioners who were constantly occupied with destroying one another, only to be reborn again. All the portals leading out of this layer were guarded.

Layer 651: Nethuria
Realm of Vucarik, Consort of Chains.

Layer 652: The Rift of Corrosion
Lordship over this layer was disputed.

Layer 663: Zionyn
Realm of the Obyrith lord Obox-ob, Prince of Vermin. It was a vast and inhospitable vermin-infested land with oceans of thick resin.

Layer 665: Unnamed
A bottomless black void where victims fell until they died from dehydration, or the winds flayed the flesh from their bones. Certain types of magic were dampened, so while spells like fireball and lightning bolt functioned normally, feather fall and levitate did not. Although several portals led into this layer, there were no portals leading out.

Demonwing
This layer was transformed by Demogorgon into a flying stone-walled ship capable of navigating between planes. It was put under the command of the balor Straoth.

The Plains of Rust
This layer had once been a neglected swamp with intermittent portals to the Nine Hells. When devils discovered this connection, they set up a colony in the poisonous swamp. Upon discovery of this invasion, Orcus and Juiblex combined forces to strengthen the poisonous nature of the plane and imbue it with necrotic energy, causing all iron and structures on the layer to decay and crumble, until all that was left was a tightly packed layer of rust and ruins, inhabited by undead and evil constructs. The portals to the Nine Hells remained since buried and unusable.

The Spires of Rajzak
This layer was a vast desolation of canyons and rocky spires. It was inhabited by masses of rampaging demons and its maddened demon lord known as Rajzak. He was said to have once been a beautiful demon lord who was transformed into a bestial creature after a conflict with Graz'zt.

Appearances

 * Adventures
 * Tales from the Infinite Staircase • For Duty & Deity • Out of the Abyss