Tale of a Gun
Tale of a Gun is a short story from The Road to War, volume two of the Course Books. This story begins with Hunter Jusenkyou already a student at Gudersnipe School. It deals with his secret fear of guns, dating back to an event in his childhood (covered in Through the Night from The Path to Ascension) in which he was shot in the shoulder. The injury, more mental than physical, remains with him throughout the series.
This is the first example of him overcoming something he deeply loathes to become a better student at Gudersnipe School; first his fear of guns and later his first kill. This also reveals the genesis of his short-lived smoking habit, mentioned in a few other stories.