He's a former soldier who's been kind of drifting since the war wrapped up. His real expertise lies in sabotage and close-quarters fighting—he fights with a pair of daggers and knows how to make them count.
What's interesting is that both he and his adopted sister Akari share a rare ability called the Iron Blood Transformation, which basically amps up their physical strength and speed. It's a pretty significant edge in combat, though it seems to be something that runs in their particular family line rather than being a common skill.
Content compiled by AnimeList.moe from publicly available sources.
