Mordenkainen is a fictional wizard from the World of Greyhawk campaign setting for the Dungeons & Dragons roleplaying game. He was created by Gary Gygax as a player character only months after the start of Gygax’s Greyhawk campaign, and is therefore one of the oldest characters continuously associated with D&D. Once Gygax was forced out of TSR, Inc. , he lost creative control of Mordenkainen.