Greyhawk

Greyhawk is a fantasy campaign setting for the Dungeons & Dragons role playing game, originally developed as "the Great Kingdom" by Gary Gygax, ca. 1970, as a setting among his wargaming penpals. Gygax's medieval miniature game, Chainmail (1971), on which he adapted the setting for his sessions, later morphed into Dungeons & Dragons role playing game (1974) when merged with Dave Arneson's more fantasy oriented setting Blackmoor. The World of Greyhawk boxed set published in 1980 was not the first campaign setting published by TSR Inc.; however it the setting most identified with early development of Dungeons & Dragons and Advanced Dungeons & Dragons.

Greyhawk was initially conceived by Gary Gygax as an underground dungeon oriented adventure for his group of friends which over time expanded to become a multi-layered underground complex near the city of Greyhawk, from which the campaign setting takes its name. Gary Gygax continued expanding the world to include the lands surrounding city of Greyhawk and finally the continent and the fictional world of Oerth in its entirety.

Integration into Dungeons & Dragons Online
Neither Turbine or Standing Stone Games have officially licensed the Greyhawk intellectual property from /. A number of older modules that were originally set in the Greyhawk campaign setting have been licensed and brought to DDO in a generic unnamed world or have been placed in the Forgotten Realms in the same manner as those reworked modules have been for 5e Pen and Paper. With a large number of players familiar with the original pen and paper modules some assume they are set in the Greyhawk campaign setting. The Temple of Elemental Evil, as a part of Update 25, is the first of the older modules placed in a non-named world. The story line from the classic module was added to DDO in Update 32.

As of August 2023 there is one public instances and no wilderness adventure areas set in the unnamed world that players have assumed to be the Greyhawk campaign setting. The quests are accessed via dimension gate in the The Gatekeepers' Grove.
 * Introduced in Update 50 the Saltmarsh wilderness adventure area, from Sinister Secret of Saltmarsh is set in the Forgotten Realms in 5E, located between Neverwinter and Thornhold on the Sword Coast. Originally created by TSR U.K. office for inclusion in their magazine 'Imagine' for the Pelinore campaign setting, when the first module, 'The Sinister Secret of Saltmarsh', was published in the U.S. it included a reference to a potential location in the Greyhawk setting.
 * A public instance, Temple Grounds was created for The Temple of Elemental Evil in Update 56.

Quests from Pen and Paper modules that were located in the Greyhawk Campaign Setting
Against the Slave Lords
 * Slave Pits of the Undercity
 * Secret of the Slavers' Stockade
 * Assault on the Aerie of the Slave Lords

The Sinister Secret of Saltmarsh

Temple of Elemental Evil
 * Temple of Elemental Evil Part One
 * Temple of Elemental Evil Part Two

White Plume Mountain