A manga of fighting deninquents

Kusaraki Masao is a normal 15 year-old boy. He goes to school, joined the soccer team, and dreams of a day when he can get a girlfriend. He's nice, gentle, and very, very shy with girls.
And why is this Mr. Nice Guy still single? Well....um...he has a face that resembles a gorilla--hence the nickname--Gorio. Despite his best efforts, Gorio couldn't seem to find a girl who will look past his physical visage to the tender heart he has.
(Source: Manga Freak)

From MangaProject:
Katsuo is starting a new semester,he wants to throw away his dark past and build up the bright future of his dreams. His wish was fulfilled and he was able to start his life anew... However, he instead got something he didn't wish for: A life as a self-torturing outlaw.

Noritaka Sawamura is a teenager; until this day, everybody has been making fun of him. Now he enters the high school which is an opportunity for him to restart a new life! He loves a girl of his school, but he needs to be a little bit stronger to be recognized by everybody. So he joins the Thai boxing section. His entertainment is very special, due to his master who seems to be a little mad. Noritaka will make you laugh, for sure!

Note:
My favorite passage is when Sawamura spins through a window with a helmet, his trousers missing, with crap coming out of his ass, and everybody looking at him. He is the most ridiculous man in the world at this moment!