Before he became "Killshot", Derek worked as a killer for hire. Comments he makes during battle imply that he was once a solider. When he is called in to perform a hit in Gotham City, he decides to take on a costumed identity because, as he puts it, "When in Rome..."
Killshot targets Nocturna, but ends up killing her fiance instead. Batwoman comes after him and, soon after, Nocturna and her lover, Night-Thief, join the fight. In the ensuing melee, Killshot attempts once more to shoot Nocturna but Night-Thief dives in front of the shot instead. Killshot was then captured by Batwoman and handed over to the police.