The Neighbour No. Thirteen

Synopsis: Taunted relentlessly by his peers, schoolboy Juzo falls victim to the evil Akai. Years later, in a twist of fate, Juzo finds himself face to face with Akai once again when they are both working at the same company and living in the same apartment building. As a child, Juzo grew accustomed to Akai's torture, but he will not stand for the same thing as a grownup. Allowing a fearless alter ego to surface and do his dirty work, Juzo slowly morphs into a force much more deadly than Akai could ever have imagined.     Source: RottenTomatoes.com