Rael-keth the Unfixed

Rael-Keth the Unfixed, Demon King, the Changing One
The most powerful of all Demons and the eternal foe of Ultima the Peerless, the latter title is an assumed style taken from Rael-Hran, the previous demon king, who in turn took it from Rael-Thrain, who took it from Rael-Tor, with each master of the Crawling Caverns consuming their predecessor in order to take their place.
The original demon king, Rael-Karn, was the greatest of the primordial Abyssborn, but Rael-keth was once a mortal. Unlike its predecessors, which sacrificed both body and mind to their colossal power, existing only as a hungry will in a vortex of destructive energy, it retains both physical form and deliberate thought. It's form is roughly humanoid, but wreathed in shadow and distorted in shape, with broad wings extending from its hips, tentacles thrashing in place of legs, and seven arms, each ending in a different appendage.