I would not call Kuarn a psychopath, since he's not that level yet. Maybe he's in love with Adele, you know, the kind of boy who is too shy and instead harassing the girl he loves? Well, maybe.
Although he threw her out the window, but he was also the one who made sure that Adele landed safely and even sincerely worried if she was hurt.
Anyway, he's a moron if he really didn't realize how the Duke and families had treated Adele for 10 years. 10 friggin years!!!!