An old school manga. Remind me a lot about shojo manga in '90, bring back the past. The art, the story... I felt sooo old for understanding this manga. Lol.
I think he's the younger brother of the king's son...so another heir. The translation/speech bubbles were confusing in that one scene, but I think that was what Arisu was getting at: that he's the younger brother of the psycho prince.
Yes... That the right answer!