Dead Soul Revolver

kagami kenichi meets a demon murdering a woman while taking a shortcut home from school. he is rescued by tsukishima miyu, a gun-wielding girl. she explains to him that the demons were once humans and the only weapon against them is guns. he soon discovers his classmate, hirai, is a demonized human when he is attacked by him. later on, miyu makes a contract with kenichi and uses his soul energy to summon a “demon exorcising weapon” and kill the demon… from baka-updates: when a person who under goes extreme depression/anxiety, loses control, a person will become a demon consumed by darkness. luckily there are those devoted to hunting those demons. boy meets monster while taking shortcut home from school, is rescued by a girl with a gun. monster gets away. later on, girl makes contract with boy and uses his soul energy to make a big gun and kill the monster…