Board Thread:Lore Discussion/@comment-71.226.242.68-20131113201112/@comment-5647122-20140717035357

Well, actually, only lesser daedra can be destroyed by killing them in Oblivion. Princes can't die permanantly anywhere. There's a specific trick to killing them. You have to destroy their entire realm, completely, and then kill them. Or somehow sever them from their realm, then do the same.