When Brandon discovered this and confronted Harry, he was murdered, but Harry had no idea of the future consequences of his betrayal.
Although Harry lacks the physical strength and agility of Brandon, he is charismatic and extremely cunning. In the anime, it is portrayed how the guilt of murdering his best friend drives him close to madness.
spoilerIn the video game he is not fought directly, instead he summons Big Daddy, who had been transformed into a grotesque monster to eliminate Grave. When Big Daddy's twisted form is destroyed, Harry realizes he has nothing left to protect himself. Harry calmly accepts his defeat and allows Grave to kill him.