The Abyss

The Abyss is where the stuff of creation leaves the world. It is the run-off, the drain, where all the filth and corruption should flow back into the Void. When put to the test, however, it became clogged with the bodies of slain Colossi and Outerfolk, allowing the corrupting energies of the Void to accumulate. In the chaos of the Colossus War, slain Gods and Titans also fell down, adding divine energy to a potent, horrific stew from which the first Fiends were spawned. From this, the Abyss became a place of despair and torment, far from any light or hope, from which corruption leaks back into the World.
The Pillars of Aiaos rise out of this morass to keep the world aloft. What the Pillars stand on is a subject of intense philosophical and theological debate.) As more and more corruption accumulated in the Abyss, even the Imperishable Substances of the Pillars was threatened, and a new type of fiend, the Demons, spawned from the foulness around the Pits around the corpses of fallen Colossi to attack the Pillars directly.
These attacks were resisted by another breed of fiend. Devils were, mostly, not spawned from the Abyss itself, but rather fromed from the disharmonious souls of dead mortals. The first Devils were marshalled and ordered by a being of immense power and unknown origins known as Ultima the Peerless to defend the Pillars and, eventually, rule the world above.
The Devils created the nine fortresses known as the Hells, one to defend each Pillar. In a mirror of this, the corruption focused around the nine greatest Pits, which became the great war camps of the demonic. Those fiends who took neither side became a kind of mercenary, selling whatever services they could perform in exchange for power, resources or protection. These were the purest descendents of the primal fiends, and were known as daimons or loths.
Nine hells, nine pits, fight for control of nine Abyssal realms over three layers.

The Abyss

Open full size

The Plains of Strife

The highest layer of the Abyss is the plain of strife, a wretched fragment of materiality, somewhat akin to the Grim Plain, but wracked by fire and violence. Streams and rivulets flow down from the Grim Plain and collect in the highlands of Gehenna into the dark flood of the Styx, the river of the damned which carries the souls of evildoers into the Abyss, where they are reclaimed as manes, larvae and lemures to fill the lowest ranks of the Deep War.
It is the most visible and constant battlefield of the Deep War. This is where the forces of the Hells and the Pits clash in open warfare, infernal engines and demonic artillery supporting hosts of fiends on either side, battling over the forges of Khorundam, the banks of the Styx and access to the key strategic passages of Escharon and the Fathomless Vertex.
The Plains of Strife are surrounded by the fathomless, ink-dark waters of the Black Ocean, which stretch away in all directions as far as the mind can comprehend. The Ocean fades at its furthest extent into the corrosive nothingness of the Void. Its waters erode whatever material stuff they come into contact with, while terrible undercurrents seek to drag all of reality out into the Void. Dire beings from beyond Existence swim in these waters, and infernal warships circle the Plains to keep these things from making landfall.
1. Gehenna, the Bloody Field
2. Escharon, the Chasm
3. Khorundam, the Withering Fire

The Dismal Mansions

The Chasm Escharon descends from the Plains to a realm of darkness and desolation, where the normal laws of the material world have little purchase. Up and down are uncertain, gravity is a gamble, and survival is a matter of will more than food or oxygen. The Stygian Falls crash down into the bottomless Lake Stryge, from which flows the poison river Calax. Elsewhere, the Unresisted Force crashes from the Black Ocean into the headwaters of the Zindral.
The realms of the Mansions are less subject to the upheaval of the Deep War than the Plains of Strife. Archdevils and Demon Princes battle for control of the environment, the devils always striving to control and stabilise the shifting stuff of the Abyss, and the demons to break down all attempts at order and restore the realms to a state of chaos and entropy. Within these contested regions, small forces of fiends engage in skirmish warfare.
4. Suspiria, the Folding Mists
5. Inveris, the Shadowed Halls
6. Caradon, the Hunting Ground
7. Veridia, the Poison Garden

Mount Nadir

In the depths of the Poison Garden, great boles of tangling roots grow from the ground alongside the deadly plants. By entering the bole and fighting down through the trunk of the tree, one can emerge into the mire at the base of Mount Nadir, which 'climbs' from the underside of the Mansions into the deepest part of the Abyss.The slopes of the mountain are coated in the congealed filth of Existence and inimical to any kind of life. Stagnant springs in the mire of Incarceron conjoin into the crawling waters of the Gabalas, which runs by myriad paths to the summit of the mountain.
Open conflict on the mountain is difficult, impossible at any scale. This is a realm of ambush and assassination, not of open battle.
8. Incarceron, the Dragging Mire
9. Gorotho, the Upended Spire

Type

Planar Sphere/Grouping