A series that was published between Dungeon Magazine and the RPGA's Living Greyhawk campaign.
Jason Bulmahn is the author.
The first part, Mad God's Key, was published in Dungeon #114. An explanation of how to use the adveenture with Living Greyhawk characters was published by the RPGA as CORS4-04 Mad God's Key.
The sequel, COR4-12 Key to the Grave, was only available for RPGA Living Greyhawk play, and was retired.