Responses
I think it happened in chapter 24 when all the servants were talking about not wanting to be around him but then he found Kyon waiting for him in the dining room. I think it was then that he realized how much Kyon cared for him and he slowly started falling himself. He still had his cruel moments after that, but his whole aura around Kyon was different. I don’t think he fully realized it until Kyon tried to leave him though.
I know we're all trying to figure out who the culprit is, but I was wondering what chapter do you guys think Lucaon fell in love with Kyon?