Cult of Tzeentch
Wolfgang the Vanquisher
Man who went mad after vanquishing a greater daemon
Wolfgang lived many centuries ago and, according to Motzer, he managed to vanquish a Greater Daemon of Khorne with a knife. The Daemon left a small part of its essence in the knife, slowly driving anyone who used it mad.
Wolfgang proved to be an excellent fighter and the knife protected him from most normal magic. A group of wizards performed a ritual to stop him. The result was that he was bound in the Mirror Moors and his knife was lost. He could, however, not die, until he was reunited with his knife.