From Operation Boredom :

Yamato Onidzuka. Childhood bully, punk, and sports prodigy. His old childhood friends are terrified of him, as he used to bully and harass them on a daily basis. When he transferred to a special sport's school, it seemed like his friends' worst nightmare had finally come to an end. But now that he's back, it seems like the nightmare has returned. Join Megu, Yamato, and their 4 other friends on their hilarious roller-coaster ride known as High School!