The premise of this entire manga makes no sense. The school is just a warzone where people duel with guns, swords, explosives and whatnot and then kill eachother? Has anyone thought how dangerous these kind of highschoolers are to the society? They are basically super weapons with no trigger discipline, shrug off pistol shots like it's no biggie and have access to dangerous weapons. Also what stops a student from just buying a nuke/big bomb and blowing up the entire school in order to get rid of the competition? Why would any sane human want to teach at such a school, no the biggest question is, how any student staying there would be able to maintain their sanity. How can you keep following this girl who shoots you when she gets angry? How can you keep going to the same class where the murderer of your friend is in? The questions do not stop coming but I guess common sense doesn't exist at all in this manga and was probably thrown out for the plot.
I'm not going to rate this because it doesn't seem to be the manga for me.