Hanza sky manga

Hanzasky summary:

The main character is a delinquent feared in the whole region. He tried to start a new peaceful life full of love instead of blood but his past immediately catches up to him and reveals his true identity to everyone in the class. He meets a girl in trouble and decides to revert to his old self just to save her.... except she doesn't really need saving, beats him up and calls him weak!. He fell in love with this "flower that blooms in the battlefield" and decided to try to join the karate club (she's the captain) just to get close to her... but things aren't that easy....