The Acadechism is an instanced zone found on top of Crushbone Keep. Climb the wall west of the Keep at ( -1112, 124, 6 ) /waypoint -1112, 124, 6 and follow the cliff path. You will find the door on the roof of Crushbone Keep.
Named mobs in this zone grey out after level 73. This zone has an 18 hour success lockout.