Dead Soul Revolver
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...
manga
on hiatus
2008