Gewalt: Aoiro Terror x Seishun Graffiti!!

Ruito is an ordinary high school student. Too ordinary... almost transparent. But when one day, thugs are attacking him before his supposed "friends", he is humiliated, exposed; his true nature is revealed, he realizes that his social life is now impossible. Then lost, Ruito decided to move the "other side", the hard, the violent side. But during his initiation, between satisfaction and doubts, meetings and missteps, despite himself Ruito will awake old rivalries and start what could become an open war!

(Source: Manga Sanctuary)