Return of Hadrach
One of the Outer planes
This layered plane of the Abyss begins as gargantuan canyons and yawning chasms in the fabric of the other Outer Planes, bordered by the foul waters of the River Styx. Coterminous with all of the Outer Planes, the infinite layers of the Abyss connect to one another in constantly shifting pathways. There are no rules in the Abyss, nor laws, order, or hope. The Abyss is a perversion of freedom, a nightmare realm of unmitigated horror where desire and suffering are given demonic form, for the Abyss is the spawning ground of the innumerable races of demons, among the oldest beings in all the Great Beyond.
The Abyss has the following traits:
Divinely Morphic and Sentient: Deities with domains in the Abyss can alter the plane at will, as can the Abyss itself.
Strongly Chaos-Aligned and Strongly Evil-Aligned
Enhanced Magic: Spells and spell-like abilities with the chaotic or evil descriptor are enhanced.
Impeded Magic: Spells and spell-like abilities with the lawful or good descriptor are impeded.