Tsathoggua, also known as the Sleeper of N'kai, is a dark deity, and being one of the main Great Old Ones. Tsathoggua is a particularly devious avatar who has a fatigue fueled outline. He is said to be great in girth, very squat and pot-bellied. He has a huge, toad-shaped head.
His drowsy lids are half-lowered over his globular eyes, from which trickle a phosphor-like glow. The tip of a queer tongue protrudes from his fat mouth. His whole body is covered with short, dark, fine fur, giving the impression of a bat or sloth.
Tsathoggua is sluggish by nature. Even when ravenously hungry, he will not arise from his place, but waits in divine slothfulness for the sacrifice. It is said that Tsathoggua came from black, lightless N'kai: the deepest level of a system of caverns beneath Oklahoma.
The worshippers of Tsathoggua in N'kai were peculiar-sensed beings which had no light at all, but which had great civilisations. In form, they seem to have been amorphous lumps of viscous black slime that took temporary shapes for various purposes.