One of the Discworld's most implacable gods, and very difficult to understand. He looks like a pleasant, middle-aged man, but his eyes are starry voids. It is possible (although difficult) to bargain with him, but proverbially impossible to cheat him, although this has been done at least once. (When Cohen the Barbarian rolled a 7 on a six-sided die by cleaving it in half in midair.) He is known to play games against The Lady using mortals as pawns, and always plays to win. His Temple is situated in the Gods' Quarter of Ankh-Morpork. It's a small, heavy, leaden temple, where hollow-eyed and gaunt worshippers meet on dark nights for predestined and fairly pointless rites. He is said to come from a world other than the Disc.
He appears in The Colour of Magic, Mort, Interesting Times and The Last Hero.