Fort Bones is a fortification in Karrnath, on its border with the Talenta Plains. It's role as a military fortification was established in 903 YK, but it's history goes much further back. It is currently lead by Alinda Dorn, a Bone Knight.
It was formerly the seat of governance of a priest of the Blood of Vol named Gyrnar Shult, but was seized by Karrnath early during the war, in 894 YK. The warlord, Kaina ir'Durna, intended to use the fort as a garrison against Cyre. The priest warned Kaina that the fort was within a manifest zone to Mabar, and that they would need to perform rites to suppress the influence of the plane. Kaina was a follower of Dol Arrah, and did not heed the seeker's advice.
When Mabar entered a coterminous phase in 896 YK, its full fury was unleashed on the Odakyr region. Plants withered in their fields, and animals dropped dead. This single event was a significant contributing factor in the famines that ravaged Karrnath and ultimately led to them turning to the Blood of Vol for help. Kaius granted the keep back to its original owner, who renamed it Fort Bones (though actual bones would not be present in its construction until decades later).
Fort Bones withstood many sieges throughout the war, and it weathered all of them, until the elves of Valenar assaulted the keep in 990 YK. The elves overran the defenders and sacked the fort, killing the commander and even stealing the remains of Gyrnar Shult. The new commander, a bone knight named Alinda Dorn, vowed to rebuild the fort from the bones of her enemies.