To the latest chapter I think they(the antagonist, maybe the empress) are killing the real fiancee and replacing them with witch one.. in short they are no longer the fiancee but just a mere witch/monster.
My thirsty ass could never be a shoujo-girl character. I'd be like "so my presence heals you? Have you thought about trying INTERCOURSE? Yaknow, uhh... for science!"
I re-read this every once in a while. It's soooo fun. Hope it's updated soon