Greyhawk

Greyhawk is a fantasy campaign setting for the Dungeons & Dragons role playing game originally developed by Gary Gygax as a setting for Chainmail the medieval role playing game that later morphed into Dungeons & Dragons when merged with Dave Arneson's Blackmoor in the 1970s.

Integration into Dungeons & Dragons Online
Set in Kron Hills The Temple of Elemental Evil, as a part of Update 25, brings characters and players to the World of Greyhawk for the first time.