Castlemourn is a post-apocalyptic fantasy setting where kingdoms fight for power through political intrigue and outright warfare; where the brave seek their fortunes in dangerous ruins, and where everyone fears the unspeakable evil that shadows their land.

Castlemourn is a land searching for its past. Its people are unaware of their origins, the greatness of their history, or what disaster brought about the dark age that has engulfed the land. Some three hundred years before the setting's current era, there existed a magical place of shining towers and marvelous wonders called the Realm of Castles. Legends tell of a great war against fell creatures that destroyed the realm, leaving scorched ruins and crumbling citadels. Whatever befell this realm was so terrible that the gods have ''cordoned'' it off.

No one is permitted to leave Castlemourn and those who find their way there, do so at their own peril, as adventurers, treasure hunters, and questors scour the land searching for relics, artifacts, and clues to their past.