The Abyss¶
"The abyss is an empty plane filled with incorporeal, immutable demonic essences, which are always struggling to find a way out." — Demons (S019)
Contested
This page is named in the open questions Seven Hells or Nine Layers (the 2026 Cosmology Revision and its predecessors count seven hells held by seven archdemons; the Fifth Age demon notes count nine layers of Hell and name them), Netherworld: plane of souls or plane of Faerie (one 2026 account places the Abyss inside the Netherworld) and Dae'medeis and Dae'cilias (the demonic terms are assigned differently by two documents of the same layer).
The Abyss is the prison of the demons.1 "The Abyss was created by the Gods during the Demonic Wars as a set of prison planes to hold Demons and other outcasts. The Seven Hells were originally Astral Shards repurposed as prisons" (S001). An outer plane with no position in space relative to the Material, it was walled off from the world by a second plane, the Mithis Plane, and when that wall decayed the Abyss ceased to be very different from the heavens its shards were taken from.
Also called: Hell, the Hells, the Seven Hells, the Abyssal Plane, the Abyssal Planes.
Origin¶
"Each shard (one of the seven hells) was initially governed by an Einar Warden, but eventually each fell to the Demons, and the Seven Archdemons claimed one shard each. Over time, the Mithis barrier was repurposed by mortals as a magical power source and slowly weakened. It began to significantly decay shortly after the Age of the Dark Sun" (S001). The Cosmology of 2022 names the makers as "the Old gods (Kalari)" and dates the plane's making "much later" than the Primordial War, when "the younger gods" needed "a way to deal with the Demonic crises" (S013). The Nature of Magic puts it at the end of the Age of Demons: "Kalar created the Worldstone to banish the demons to a sub-plane known as the Abyss. There the Demons have largely remained, trapped" (S208). The player's introduction to demons says the same in the common tongue: "During the Demon Wars several millennia ago, the mortal races, with help from the Gods, drove back hordes of demons and imprisoned them in a separate plane of existence: the Abyss (also called Hell). Since then, demons occasionally slip from the Abyss into the mortal world either through rifts or are summoned by reckless spellcasters" (S334).
Why the prison holds is a matter of souls. "When the Abyss was formed from Astral Shards, all Demons and their forms and souls were bound to it. A Demon can only walk on other planes when their soul is possessing another form ... or as a projection. Without a form to hold them on a foreign plane, the Demon's soul travels instantly back to the Abyss where it is reborn into a Demonic Form" (S421). The history of the earlier ages tells it as the turning of the war: demons were "caught and bonded with the Abyss so that when they reformed, they reformed in the Abyss and not the Material. This act turned the tide against the Demons, and their numbers quickly dwindled, until they were all exiled to the Abyss" (S386).
The Seven Hells and their lords¶
"Ages of working in direct competition with one another as well as the significant thinning of demonic populations due to soul drought and raging inter-demon conflicts, there are now many fewer demons than there were during the Demonic Wars. The abyss is now ruled by the remaining five archdemons: Asmodeus (holds 3 shards), Bhaal, Mephistus, Belphegor and Mammon. Their conflict has been even more intense since the betrayal of Asmodeus (during the Hollowing Period). Two other archdemons have either been destroyed or are sleeping/hiding (Leviathon and Luciferon)" (S001). Seven shards, five lords: the arithmetic of the Revision is three for Asmodeus and one each for the other four. The archdemons themselves are described elsewhere; the plane is their estate.
The Fifth Age demon notes count the estates differently. "Each archdemon is an Astral Shard holder (one or more of the 9 Hells) and a rival of the others", and the layers are named (S022):
| Layer | Holder | Notes from the source |
|---|---|---|
| Asphodel | Asmodeus, formerly Leviathus | "A place not unlike the material realms, but devoid of life, rocky and barren." |
| Minos | Asmodeus | |
| Acheron | Belphegor | "Cold and Wet." |
| Plutoph | Mammon | |
| Styx | Bhaal | |
| Lethe | Mephistus | |
| Phlegethon | Asmodeus, formerly Luciferon | |
| Malebolge | Mephistus | |
| Cocytus | Bhaal |
Asmodeus "is rumored to have used his newfound power to destroy Luciferon and Leviathus, wresting control of 2 additional layers of Hell", and holds "25% of all the demons in Hell (though a majority of them lesser)"; Bhaal "the most numerous (30%) and most powerful demons in all the Hells"; Mephistus 15 percent, "all of them fanatically loyal and powerful"; Mammon 20 percent; Belphegor 10 percent, "all of them very powerful" (S022). The same source's descriptions of the nine layers as circles of sin and punishment are a real-world reference pasted into the notes, not Terrun lore, and are not integrated here. The ascendants' council of the same year also speaks of "the nine" when it calls Asmodeus "one of the lesser of the nine" (S031).
The archive's own count is seven: the Compendium's "7 Archdemons, Demon Princes" are Bhaal, Mammon, Asmodean, Leviathus, Belphegor, Mephistus and Luciferon, each "the most powerful of one of the seven types of demons" (S372, S384), and the demon classifications of 2016 and 2018 rank the same seven above the Demon Princes (S512, S518). The Sancturi campaign has Asmodeus "undisputed ruler of the Demons. He has defeated 1 of the other archdemons and subjugated the other 5 (He keeps them in the Abyss)" (S132).
Since the barrier fell¶
"Since the destruction of the Mithis Plane, there is no real distinction between the Astral Plane and the Abyss; both exist in extradimensional space and both are made up of sovereign matter. The archdemons have also managed to claim additional astral shards once owned by the dead gods, making them stronger than ever" (S001; "both exist floating in the Astral Sea/Inner Void" in S013). The Fifth Age magic notes record the consequence for the world: "Demons are no longer confined to the Abyss and can navigate freely across the planes" (S014), and where once "demons commonly projected their spirits out of the abyss when summoned to take possession of material forms ... Now they are able to be summoned with their fully manifested demonic forms" (S018).
The Redemption reversed some of this. "The Mithis Plane is still a bridge between Material and Abyss (but much more distant). Asmodeus still has a lot of control here", and among the declining powers of the age after it are "The Archdemons, especially Asmodeus. Re-imprisoned in the Abyss" (S112). The Acadian notes of the Fourth Age offer a different placement altogether: "The Abyss is a fragment of the Mithis subplane", located in the Netherworld below the Material (S358).
The nature of the plane¶
"Like the Transitory Planes, they are only a set of small domains (7) floating in a much larger sea of nothingness. The Abyss itself is located within the Inner Void (The part of the void where return is still possible)." "Portals to the Abyss are very difficult and considered by most planar travelers to be suicidal. Any being showing up in the middle of a horde of raging, hungry demons would want a very strong reason for being there. Killing a demon in the Abyss is not a permanent death, for they will reform and regenerate their material form over time. It is not uncommon for spell casters to pull demons from the abyss to inhabit forms on the material plane" (S421). The demon lore of the Fifth Age layer sees the same place from inside: "an empty plane filled with incorporeal, immutable demonic essences" (S019).
Death here is cheap and permanent death forbidden. "Death in the Abyss has little meaning for demons as they simply respawn ... However, Energy death in the Abyss is possible, but is strictly outlawed by the Archdemons, who reserve its use as a form of capital punishment. However, in the history of the Abyss there have been a many wars between Archdemons that have led to mass energy deaths and the complete destruction of many demons" (S518, S512). A demon slain on the Material "re spawns almost immediately in the Abyss near the place in the Abyss that is attuned to his earthly mortiquery. If his mortiquery does not exist, he will respawn more slowly in the place in the Abyss attuned to where his form was killed/separated" (S518). "While in the Abyss, a Demon killing another Demon has little effect. The Demonic Form simply reforms" (S421).
"Material forms may visit and reside in the Abyss." The archive cosmology adds that "because of a lack of a connection to the Negative or Positive Energy Planes ... Divine Magic does not function in this plane" and that the Abyss "connects to the Mithis Energy Plane and the Ethereal Plane" (S421); the newest statement of Astral Law instead counts the Abyssal Plane among the planes it governs and says divine energy is available there (S205). The Fifth Age demon lore agrees that the Abyss is a place a demon's thread can reside and draw power from, like any other plane (S019). The oldest magic rules let a caster "draw on the fabric of the abyss to merge it with their current plane to create things like Abyssal rain, Hellfire" (S371).
Abyssal biomes¶
The Abyss has terrain. Two Sancturi-era catalogues name its biomes, the later as the raw material of Hollows ("the properties of every Hollow can be determined from a combination of the Abyssal Terrain and Fae domain that it is associated to", S156), the earlier as the homelands of the demon kinds (S114).
Seas. The Scalding Sea, "boiling water, steam"; the Sulfuric Ocean, "acidic seas"; the Putrid Waves, "a rough sea of brown wastes and floaties of rotting materials" (S156); and the Umbral Sea, "boiling dark deep waters, steam and rocky barren islands. Home to Sea Demons" (S114).
Plains. The Pale Night, also Darklight: "Dim light, Dusty, Empty, Sleepy, Shadows and Nightmares. Home to Night and Shadow Demons." The Black Tundra: "very cold, black snow wastelands. Home to Horned and Frost Demons." The Oozing Plains: "a rocky, pockmarked plain which supports some plant and animal life, but is a perfect habitat for oozes and slimes. Home to Sludge Demons." The Xanthous Morass, "Land of a Thousand Eyes": "hot, infested yellowed jungles and swamps, living wood. Home to Plague, Bog and Sludge Demons." The Steaming Fen: "thick swampy vegetation, steamy and Burningwater (Blue fiery water). Home to Bog and Fire Demons." The Rotting Fields, "a rolling landscape covered with rot, fungus and waste", and an unnamed snowy plain (S114, S156).
Hills and mountains. The Iron Wastes: "a dreary cold place filled with sharp edges and jagged countryside. Home to Blade and Rock Demons." Brimstone: "a domain of fire, lava, smoke and choking sulfur. Home to Horned and Fire Demons." Sulfuron: "sulfurous lands filled with volcanic pools, acidic lakes and rivers, lava flows, and the stench of sulfur. Home to Horned, Fire, Bone and Acid Demons." Wormblood: "Blood red vegetation, jungles, seas of blood. Home to Pain, Bone and Blood Demons." The Crystal Bog: "broken and rocky land filled with water and crystalline formations. Home to Horned Demons." The Creeping Fungus, also the Fetid Forest: "dark and rocky landscape covered with fungal forests and tainted ponds. Home to Bone and Plague Demons." The Slime Pits, "underground caverns filled with slimes and oozes." The Plague Hives: "many breeds of competing buzzing insects build multi-colored hives in caves across these rocky landscapes. Home to Plague Demons." The Ashlands, also the Korakul Ashlands: "Lava, Ash, Volcanic Rock. Home to Acid, Fire and Shadow Demons" (S114, S156).
A Hollow of the highest class is this terrain brought into the world: at its core it has "essentially merged the Abyss with the Material", and a thing fully hollowed "no longer bears any resemblance to its original form and now is purely associated to the Abyssal Plane" (S146, S325). The creatures of these biomes are on Demonic Forms and Hollow Creatures.
Dae'medeis¶
Dae'medeis is the demonic word for what holds a demon together. In the newest usage it is Essence: "Essence (Dae'Medeis) represents the core of a singular demonic entity. It is a measure of a demon's power and identity" (S334). It is what the Abyss is full of. "Their souls are unlike other souls in the Terrun cosmology and are casually referenced as Demonic Essence, or formally as Dae'medeis. This is the basis for a common misconception: Demons have Essence and not Souls" (S019).
The facts about it that the sources call "mostly agreed upon" (S019): essence "is neither created nor destroyed"; it "can be captured from other demons, siphoned off by magics or it can decay back to the abyss"; outside a possessed form "Demonic Essence decays at a rapid rate, returning to the abyss"; "when a demonic Essence is returned to the abyss, a large portion of that essence is split off and forms manes (the smallest unit of sentient demonic Essence)"; and "demonic essences arrive through rifts which are tears between the abyss and other planes that allows a specific amount of Essence through before sealing again." The counterweight to the Abyss's pull is Bond (Dae'Cilias), "the tether keeping the demonic essence from being drawn back into the Abyss"; when it fails, "the Demon's essence is banished to the Abyss" (S334, S333). A spirit newly crossed over "begins decaying almost immediately and they have a short period of time to find and possess a host" (S333).
The older demon lore uses Dae'medeis for the Demon's Thread, Dae'cilia, "another name ... frequently used by warlocks and mortal scholars", also called "the Demon's Soul, Demon's Heart or Demon's Magic" (S019); the newer handout separates the two words as above. Essence, Bond and the mortiquery are described on Demons; the Chained Soul of the archive cosmology, by which a demon "anchor[s] themselves to this existence", is on Souls and Spirits.
Earlier accounts¶
The Compendium lists "The Abyss (Seven Tiers)" among the Outer Planes and records that "Mephistus, Asmodean and Belphegor escaped during the early Demon wars", their souls thereafter "reborn into mortal forms after each death", so that the archdemons who escaped had to be held in possessed mortal hosts because they were "too powerful to banish back there" (S372, S384). The Compendium's age of Faerie has Kalas form "a new plane (the abyss), and in the process split the earth and did massive damage to the elemental and astral planes" (S372). The oldest rules treat the Abyss as an Inner Plane reached by Conjuration (S371). The Sancturi-age roll of archdemons places Belphegor and Bhaal "in the Abyss", and Asmodeus and Mephistus imprisoned on the Material by the Light of Kalar (S124). The archive cosmology also says that in the Abyss "the demons attempt to penetrate weaknesses in the Mithis Plane and project their spirit to the Material Plane, where they can then attempt to possess weak forms" (S421).
In Play¶
Mortals do not go to the Abyss; it comes to them. The thin places in the barrier, Spawning Rifts, Demonblight and Demonic Rifts, are on the Mithis Plane page; the Hollows, "demi-planes between the Material Plane and the Mithis Plane" that "form a strong connection to a particular part of the Abyssal Plane", have their own page. A traveller who does arrive will find "a horde of raging, hungry demons" (S421) in one of the biomes above, and should expect that killing any of them changes nothing.
Gap
No source says which of the Seven Hells bears which name, which biome lies in which hell, or what any hell looks like beyond the two phrases in the layer table. The Einar Wardens who first governed the shards are unnamed. Nothing describes the entrances to the Abyss or who controls them.