I think Kana actually doesn't like Naho that much and only want Naho to depend on him and controlling Naho tbh was easy. He may just want Naho to only look at him. Obsessing over Naho bcs Naho was kind to him. He may wants to make Naho his bcs Naho doesn't care about his face and will not fight for him (if this makes sense) just like girls fighting over him when he's in kindergarten
I think Kana actually doesn't like Naho that much and only want Naho to depend on him and controlling Naho tbh was easy. He may just want Naho to only look at him. Obsessing over Naho bcs Naho was kind to him. He may wants to make Naho his bcs Naho doesn't care about his face and will not fight for him (if this makes sense) just like girls fighting over him when he's in kindergarten