In the Guild of Cerberus
Once a temple to the Demon Overlord, is now is eternal Prison.
During the Age of Demon, Gilmesh was the Demon Overlord that control a better one half of land we now know as Breland. He controlled countless horde of lesser demon that help me enslave the lesser being and lay seige to the surrond land. But he was never satished with his domain , which lend him to start to conquer the Lesser Demon Overlord land.Initailly he was very successful in his conquest but when he try to conquer the land of Lloth, his army was devested with in a week. the event that happen next was lost from history but we know that Gilmesh was eventually seal in his temple.