Tharizdun (Dark God) [Intermediate God]:

What manner of Power Tharizdun is is unknown, although his name is associated with loss of strength and sanity, exhaustion and cold, fatigue, mind-bending illusions, depression, catatonia, and paralysis. Legends says that Tharizdun is banished and imprisoned in some unknown demi-plane, but there are those who strive to bring their old master forth. What manner of madmen, or which creatures, served him aeons ago is unknown. The Scarlet Brotherhood is said to revere Tharizdun and to seek his release through the use of a mighty artifact of evil.

Worship of Tharizdun takes place in unknown subterranean temples of chill, darkness, and insanity. Such places are highly secret, and many are lost and ruined. Litanies of this Power are hideous in extreme. Most folk feel that the less they know about the Dark God, the better they like it. Even mention of his dread name is held to be a danger.

Tharizdun's priests:

The sole duty of this priesthood is to free Tharizdun from his prison. They sacrifice all to this end. The extent and location of the priesthood is unknown.