The Abyss

There are multitudinous layers of the Abyss, perhaps even an infinite number. No one has ever catalogued them all, and it's doubtful that any of the plane's natives, let alone any other bean counter, has ever considered the effort worth the time and danger. Plain and simple, no one's ever done so because each layer is so horribly grotesque that a berk would have to be barmy to want to see any of them. Even fewer sods have the power to actually do so and survive. For one thing, almost every layer of the Abyss is completely inhospitable. For another, this plane is home to the tanar'ri, one of the two races locked forever in the infernal Blood War and they aren't particularly hospitable either.

Geography

There's no single unifying theme to the physical nature of the layers of the Abyss, except that they're all incredibly harsh. Some are endless deserts of baking sand, salt, or even rust. Others are nothing but bitterly cold ice plains, with razor shards of ice dotting the land. Some are endless seas of stinging salt or smoking acid. Others are plains of rock and lava, with atmospheres of choking fumes. Still others are unimaginably worse.
There's no single unifying theme to the physical nature of the layers of the Abyss, except that they're all incredibly harsh. Some are endless deserts of baking sand, salt, or even rust. Others are nothing but bitterly cold ice plains, with razor shards of ice dotting the land. Some are endless seas of stinging salt or smoking acid. Others are plains of rock and lava, with atmospheres of choking fumes. Still others are unimaginably worse

Fauna & Flora

Eyewing, fetch, fire shadow, quasit, retriever, and tanar'ri all reside in the Abyss. A short list of the powers here includes Sess'inek of the lizard men, Laogzed of the troglodytes, the beholders' Great Mother, and virtually the entire drow pantheon. Chemosh and Hiddukel (of the DRAGONLANCE saga) and Beshaba and Umberlee (of the FORGOTTEN REALMS setting) also claim the Abyss as home.

Natural Resources

unless you plan on looking for a vaction home for your worst enemy the abyss has little to offer, the plane is considered inhospitable for a reason berk.

Type

Dimensional plane