Hyper Broken ~Tamashii no Chikara~

The protagonist thinks that he is the strongest fighter around his school, until he got totally trashed by a new rival. If that wasn't bad enough, his sister got murdered and he was left for dead in his burning house. He got saved and found out that he has the potential to become the strongest person on earth. Will his girlfriend and other friends be able to keep him from the revenge-driven dark side of his power? [edited from Li's Fun House]