My Bodyguard(1980)

Clifford Peache is the new kid at a Chicago high school who find himself the main target of the schools resident bullies. While attempting to defend himself he is saved by Ricky Linderman the school outcast who's rumored to have killed his own brother in cold blood. The bullying stops and the unlikely pair become fast friends until The bullies find their own champion to take on Ricky who refuses to fight back and then disappears. With Ricky out of the way the abuse continues until Ricky shows up to face his rival along side Clifford who is facing off against Melvin Moody the bullies leader.