He is hired by Jack to help defend Tamagashi Village which comes under attack by bandits, led by Akuma, once a year under the black moon. Yuudai willingly accepts the invitation to help out, ditching his old job at the port, and soon becomes good friends with those in the group, especially a mute girl called Neko, and the two quickly become close friends.
After successfully beating Akuma and his bandits, Yuudai elects to stay with the villagers to protect their village. It is suggested that a romance may be forming between him and Neko.
Yuudai is a tall broad warrior and though he may appear to be fearsome, he has a gentle heart, (first shown when he refuses to kill a mouse and lets it go instead upon capturing it), and is very good-natured as well as a good leader. He's a good constructor; in The Ring of Fire he makes a barricade so that Akuma and his "army" cannot pass.