he has a magical bond with than that lets him know what they are feeling, and them know what he's feeling. Also they are clearly not slaves because one of them almost kills him because she didn't have enough knowledge/self control to fight her instincts. He's just lucky that the monsters feel affection for him because he gave them a sense of self and are predisposed to liking him like a child is to their mother.
Which to be honest, since their born from him and gain similar personality traits it doesn't help much in growing your personal skills. The only one that isn't seems more a listener and advisor than a conversational partner.
He has rules that limit what he can do, but when push comes to he finds ways around them.
I think that's really just a misunderstanding of the MC, plus you can think a rose is beautiful or good looking without wanting to do it. I think he just has trama from his pass life and once he gets over it he'll have a great time.
It's to make people afraid of him.