Gaku Hikitsuri is a high school student attending Akademi High.  He is a well-known but feared delinquent as rude, violent, and ruthless.  Gaku used to be a victim of bullying, hence the reason why he became a delinquent in the first place, alongside other his 4 bullied friends.  With his 4 friends, counting 5 with himself, they masked themselves by putting a tough persona act so they wouldn't be seen as weak nor be victims of bullying anymore.