Unleashed (2005)

Crime boss Bart raises orphan Danny with no knowledge of anything other than how to fight, using him as an enforcer when debts must be collected. Planning to enter Danny into a fight tournament and retire with the prize money, Bart disappears after a deadly drive-by shooting. Danny flees and takes shelter with piano tuner Sam. Away from Bart's abusive control, Danny learns how to live like a human and begins investigating his past.