Tharizdun is the god of Eternal Darkness, Decay, Entropy, Malign Knowledge, Insanity, and Cold. He was imprisoned ages ago by a coalition of deities to prevent the destruction of existence itself. Although imprisoned, Tharizdun still has a degree of his original multiverse-threatening power.
Tharizdun's doctrine is simple, to destroy everything (himself included). Tharizdun is credited with saying: "The very threads of existence must be torn asunder, then burned, then the ashes scattered, until all is nothing and no one exists to remember existence."
Tharizdun's worshippers are often insane, and their ultimate goal is to free their dark deity from his prison. Because of their god's nihilistic doctrine, he is the enemy of all and an ally of none. Tharizdun is sometimes worshiped by nonhuman aberrations such as aboleths, neogi, and grell.