When a sinful mortal soul is judged and sent on to the Abyss, it can become a deadly fiend—a demon. Demons are living incarnations of sin—be they classic sins like wrath or gluttony, or more “specialized” depravities like an obsession with torture or the act of treason or treachery. Once formed, a demon’s driving goals are twofold—the amassing of personal power, and the corruption of mortal souls to cause them to become tainted by sin. In this way demons ensure a never-ending supply of new demons to bolster their ever-growing ranks in the Abyss.
Though now the most plentiful fiends of the Abyss, demons are relative newcomers, spawning only as mortal influence—and mortal sin, in particular—began to shape the plane. For eons, demons fought with other longstanding residents of the Abyss for dominance, but eventually their sheer numbers allowed them to become the predominant chaotic fiends.