Lethal Ninja (1991)

The city has been taken over by a vicious, Mob-connected teenage gang and their deadly leader, a mysterious Martial Arts master known only as Sonny. In desperation the Mayor and Police Commissioner hire karate expert and mercenary vengeance fighter, J.D. McKay, to save their ravaged city. McKay eliminates the ruthless thugs with pin-point precision until there is only one left... Sonny... McKay's boyhood friend turned killer. They were boyhood friends. Now they are enemies. One is destroying the city... The other has been hired to stop him.