I can have a hard time with slave AUs too, but have you read "Stephen" by amproof? It can be seriously triggery, but the twist on the whole slave cliche and the amazing characterization make it one of the best-- if not the best-- of the fics I've read in this fandom.

My friends had to talk me into reading it because I wouldn't go near it once I found out the setup, but I am so very glad I listened and read it despite my misgivings.