The Formless Wastes, also known as the Chaotic Abyss and the Land of Lost Souls, are those regions of the Immaterium that do not fall under the dominion of one of the four Chaos Gods. Much of its landscape is simply a terrain of pure chaos that is forming and reforming constantly based on the psychic currents roiling the minds of the sentient mortals of the Milky Way Galaxy as well as the psychic currents of the Realm of Chaos. The Formless Wastes are a place where the laws of physics hold no sway. Within the Formless Wastes sit rivers of tar that flow through petrified woodlands beneath crimson skies. Great stairways ascend into the heavens where they connect back on themselves in an endless loop. These celestial stairways sit alongside castles crafted from bone and fortresses of ichor while pillars of fire burn on the horizon. Every dream, nightmare and vision ever had by one of the sentient races of the galaxy has a representation within the Formless Wastes. The Wastes are also the home of the daemonic Furies who watch for any prey, mortal or daemon, that comes within their reach.
Those Greater Daemons and Daemon Princes that are strong enough to maintain a level of psychic control over their environment within the Warp also make their homes within the Wastes. These islands of horrific stability stand out within this chaotic wilderness with some only appearing for an instant whilst others are as old as the Ruinous Powers themselves. Each of these sub-realms is a small extension of the Realm of Chaos that embodies the whims of its creator and has a shrine or temple dedicated to its beliefs. Some are even populated by daemons born from the mind of the Greater Daemon or Daemon Prince, though these entities are usually short-lived as they tend to be consumed by the Furies that populate the Formless Wastes and are much weaker than the daemons of the four major Chaos Gods.
The minor Chaos Gods are also believed to sometimes maintain their demesnes within the Formless Wastes. Also within the Formless Wastes of the Immaterium resides the dark daemonic foundry known as the Forge of Souls.
- Codex: Chaos Daemons (6th Edition), pg. 8
- Codex: Chaos Daemons (4th Edition), pp. 8-9, 44
- Dark Heresy: Enemies Beyond (2nd Edition) (RPG), pg. 136
- Realm of Chaos: Slaves to Darkness (1st Edition), pg. 212