This is a new manga that is currently on its 17th chapter. The storyline is about a bunch of delinquents fighting one another to make a name for themselves. The protagonist is Hana Tsukishima who came from the country (I think) to the big city. He is laid back and kind, but when he fights he becomes an entirely different person. Hana's goal is to become the leader of his notorious high school Suzuran.
IMO it is a typical manga but I enjoy it for some reason. If you like this kind of stuff then go check it out (it has comedy as well). If you are wondering why it's called "Worst," it's because everyone is trying to be the baddest bad ass.