Profundis
Heads up, this is a toxic psychological nightmare of smut, non-con and gore. DO NOT READ THIS AS A LIGHT ROMP. P.S - The guy who transforms? HE DESERVES THE FUCKING WORLD. EASILY THE BEST CHARACTER. That being said, considering that's not the genre I'm usually interested in this is FASCINATING. Mind you I'd like this even more if it did turn into a romance thing but the fact is that's highly unlikely as it is a adaptation of a novel. The MC is forced to inhabit with powerful insane beings who don't even treat him as a human being while he tries to maintain his sanity and his morals. I find it all darkly wondrous. Not in the "I wish that were me" but more so "What a plot! Glad it's just a story!"
Her nickname is...