On this D&D Legends and Lore, William Stark and Omar Timsah cover the Origins of the Abyss.

The Abyss is an enticing enigma within the lore of Dungeons and Dragons. Its depths unknowable. It’s animus inscrutable. A festering malignancy upon the very fiber of existence. The abyss is nihility made real. The call of the abyss has driven many a D&D character mad as they attempt to understand the plane of Chaos and Evil incarnate. And though no consensus as to its origins has ever been reached. There are two major theories that have permeated the editions of Dungeons and Dragons. These I will present thusly.