i feel sorry for him kind of as both him and Casey tried hard to be their sensei's star pulips and had this sibling rivalry thing going on, though like so many others Masazuka did not defeat his toughest opponent, which was himself which lead to his leaving the school after he tried to kill Casey in a moment of anger and perhaps trying to prove to Sensei Takeda who was the one to become soke or head of the family. Also he did not kill all of the school's students but like only 7 of them. 6 were students and 1 was the sensei.

Though he was a real asshole with an anger managment problem and was also ruthless and vindictive as he killed this guy with his own gangsta chain necklace..

Well his anger management problems was what led to his downfall, but I don't really feel sorry for him - wouldn't feel much like a good antagonist if I felt sorry for him when watching the movie!

well true, and well as with several characters like him, I always get the feeling that even if Casey was Asian, he still would have had problems with him, as he just seemed that type of person.