The fort is controlled by Zealots, it's a fairly large area with one room level. There are both caves and ruins so beware of the ceiling falling down when stepping into some rooms. Lock for secret doors, opened by buttons in the walls. There is a floor trap leading to a lower level, to get out of there push the button somewhere in the room.
Look out for gems and coins in alcoves. There are a number of chests with various loot.