Ogami Matsugorou

Old school comedic romance between two polar opposites - a girl who despises violence and a boy who knows no other way but is still trying...
Ogami Matsugorou is the biggest, roughest, toughest kid around and he's entered high school with a list of enemies a mile long and a group of supporters just as big. His whole life is about violence, although he always prays for his victims after beating them senseless. Then he meets Nagasaki Koume while doing some mandatory volunteer work at a local kindergarten - a pretty girl who despises violence of any sort. He decides to try and help out at the kindergarten, which is being terrorized by local yakuza thugs, by recruiting his gang to help rebuild furniture the yakuza have destroyed and so on. Of course the yakuza show up, and eventually they drive him to the one thing he knows well and can do better than anyone - he beats the living hell out of them, which of course Koumi disapproves of, even though she recognizes that Ogami has saved the day.