Only a fraction of all Demons live here, most preferring to stay within the abstract Primordium.
The Realm is actually composed of nine different planes, each of which is circular and hundreds of miles in diameter. It is not possible to go over the edge of the planes, and each is enclosed within a pocket universe. To go to the plane below, an individual must travel to the portal in the centre of the plane. The endpoint of the portal is usually far from the centre of the plane being travelled to.
The nine planes are as follows:
- Asphos is an ashen wasteland, with constant ash storms and uncomfortable heat. It is the fourth-largest plane and is patrolled by tens of thousands of guard-demons. Faint light is produced by luminescent clouds several kilometres above the surface.
- Magmus is a sea of lava with slabs of rock floating freely on its surface. In places there are fire geysers and rain is replaced by falling, burning gravel. A thick smog of poison gas lies over the molten rock, but convection usually causes the deaths of travellers before they can asphyxiate. There are Demon palaces on many of the slabs, and this is the third-largest plane.
- Tsevra is a plane composed of smooth, self-repairing metal with an inch-thick layer of blood that does not clot unless removed from the surface. There are forests here with red leaves that drip more blood, and there are flying and swimming creatures to be found. There is a square of light in the sky that provides illumination, and dims then brightens in a cycle that lasts about four days.
- Liphraddon is a plane without a surface; all things float freely with no gravity. There are large planetoids up to a few kilometres wide, often linked by chains and bridges for transport. There is an ambient and slightly luminescent purple mist that obscures everything beyond a few dozen kilometres away. It is the second-largest plane.
- The plane of Gehera is arid desert. Upon closer inspection, the sand grains are actually pulverised bone, and in some locations enormous ribs and skulls protrude from the dunes. There is a sun located constantly overhead that beats down and maintains a surface temperature of over 40 degrees centigrade, but also emits large quantities of ultraviolet light that cause rapid burning to unprotected skin.
- Shehezra is one enormous urban sprawl, with twisted architecture, narrow and dismal streets, and gargoyles fixed on each roof. Buttresses, spikes, and multi-tiered structures are ubiquitous and the light conditions never change. Occasionally, it snows.
- Asmanas is a plane in complete darkness. It is formed of tens of thousands of tunnels and corridors through tough rock, many of which are inhabited. Natural fire cannot not start here, but travellers can create magical illumination. Tunnels vary in width, height, angle, and in surface conditions- some are flooded, some are slimy, others are spiky, and some are rough rock.
- The plane Kathela is made from a perfectly transparent disc. Eyes cannot reveal its presence, so travellers can only feel it by touch. Both sides are inhabited, and there are hundreds of bright 'stars' to provide light.
- The largest and last plane is Khlypse, home to the most powerful Demons of the Infernal Realm. All light radiates from its inhabitants, with Ikhroth at the centre and visible even from the edge due to the lack of a horizon. The surface is cracked and broken rock and the sky is filled with a Primordium mist. Billions of Demons move about across it.
The Infernal Realm was created by a group of immensely powerful Demon Lords, most notably Ikhroth, after they discovered that Mythos was about to be created, so it pre-dates that World marginally. It acts as a staging area and is where armies and raiding parties are prepared.