Demonweb Pits

In the Dungeons & Dragons fantasy role-playing game, the Abyss, or more fully, the Infinite Layers of the Abyss, is a chaotic evil-aligned plane of existence. It is one of a number of alignment-based Outer Planes that form part of the standard Dungeons & Dragons (D&D) cosmology, used in the Planescape and Greyhawk campaign settings. The Abyss is also the name of one of the faith-based outer planes that form part of the Forgotten Realms cosmology. While the published 3rd-Edition source books indicate that the Abyss of the standard D&D cosmology is not the same plane as the Abyss of the Forgotten Realms cosmology, they are for all practical purposes identical.

The plane known as the 666 layers of the Abyss was mentioned for the first time by name in the article "Planes: The Concepts of Spatial, Temporal and Physical Relationships in D&D", in The Dragon #8, released July 1977. In the article Gary Gygax describes the plane as one of the "Typical lower planes". The plane was mentioned again in an appendix of the known planes of existence in the original (1st edition) AD&D Players Handbook, published in June 1978, where it was described as "The 666 layers of the Abyss of absolute chaotic evil".

The description of the Abyss varies between different editions, campaign settings and even individual accessories. This can be viewed as the canonical status of the Abyss changing, or as an in-character explanation that the conflicting information is the result of misinformation spread by the demons themselves, and of misunderstandings by those who study them.

One description of the Abyss presents it as a region of intense, extreme, and unforgiving climates, with layers consisting of overwhelmingly fierce desert sandstorms; explosively unstable volcanic activity, boiling lava, and molten rock; blinding, sub-zero Arctic glaciers; bottomless oceans filled with enormous leviathans; nauseatingly putrid environments saturated with disease-causing fungi; and the endless, existential void of infinite space.

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