it's no big surprise he turned out this way. after all, he needed to do this. protect himself. he's violent and ill-mannered. reminiscing of his older brother, sanemi. the brother who won't acknowledge him as his own brother at all. everything's rough between the two. so, it's really no big shocker that genya is this way. even if he has a bad temper, he's insecure beneath all that. trying to show his brother that he's good. good enough to be acknowledged as a brother. he needs to be strong.