Castle Darkhold, western stronghold of the Zhentarim, is located south of the Sunset Mountains in Western Faerûn. Originally called "The Keep of the Fallen Hills," the looming castle was built a millennium ago by giants as a summer capitol of the Giant Empires. When the Giant Empires collapsed, the Keep was abandoned and looted. It eventually became the home of the dragon Cryomantipelica and eventually, as the "Wild Hold," the base of operations for an adventuring company called The Wildmen of the North.
The castle finally became Darkhold when it was conquered and settled by the lich-queen Varalla until, in 1312 DR, the Zhentarim invaded it in an attempt to expand their organization westward. Darkhold was ruled by the wizard Sememmon until recently, when he and his consort Ashemmi vanished in response to the consolidation of Zhentarim power in the east by rival Fzoul Chembryl.
Darkhold currently houses approximately 800 warriors, and is headed by several commanders, whose sparring for position is actively encouraged by Fzoul in order to cull the weak.