Atsuyu, whose formal given name is Setsuyuu, is the self-proclaimed regent of the province of Gen in the kingdom of En. Early in Shoryu's reign, Atsuyu attempts a rebellion against the king of En, claiming that Gen's prosperity has declined due to the incompetence of the new king.
However, his actions are actually due to his massive ego and superiority complex, in which he has deluded himself into thinking he would be a better king. After years of manipulation and abuse of everyone around him, particularly of Kouya, he is killed while cheating in a duel against Shoryu.
