So I was having one of my now common troubles with the conjure dremora lord where I would summon 2 but none would appear so I summon more but then 4 of them appear at once and after they were finished killing the hoard of ash spawn I killed them and I had a pleasant surprise where I could loot each of them for a daedra heart. I tried this again and it worked again and I just repeated this and now have 50 hearts! Sometimes you don't get to loot them so you miss out on a few but the bodies turn invisible except their hair and the red that's on their armor