The Chaotic Hells of the First World
From the remains of the God's first attempt at world building come the hellish landscape that is the First World.
The First World is pure chaos with only the realms made by those powerful enough to form a semblance of order. The environment of the Hells is a roiling mass of everchanging elements barely held together. Travel without protection is deadly as the earth you are walking on could catch alight or melt into molten iron at a moments notice.
The realms around these worlds are a perversion of the second world. Created by the Hollowed who themselves are perversion of the God's their worlds are nightmare realms of unmitigated horror where desire and suffering are given form. Occasionally one of the Hollowed's agents or an Warlock of considerable power is able to wrest control and create their own bubble of calm in the hells of the First World but none are as large or as controlled as the three largest. These realms are pockets in which the fabric of chaos have slowed their relentless, changing insanity to a near-normal pace.
The Three largest domains are:
Flora & Fauna
Outside a Hollowed realm no flora or fauna exists. Inside the various realms vegetation is sparse in most hells: the Inferno having almost no plants at all save for what plants can be cultivated to kill or corrupt. The most prevalent vegetation can be found in the Demonic Wastes were plants are similar but sinister, it is not uncommon to find intelligent plants that crave flesh or types of trees that explodes in splinters to feed off blood. These are hardy plants and mosses are frequent as they spring from the imagination of Deimos but as they come from the mind of the Hollowed Demonlord even the grass can be dangerous.
The Many Layered Abyss
considers plant life to be of little use but has created a desire as plants are seen more as a sign of wealth and excess. When Devils gain access to the Second World their often will grab the first plant or tree they see. A strong or powerful devil will fill his domain with plants while the smaller weaker devils will plant a flower almost out of spite. What fauna that does survive is stubborn and able to survive the harsh landscape. More often a Devil will use it's magic to keep the plant alive creating a modified strainsof their material planes.