Kozuki Momonosuke is an inhabitant of Wano Country and the son of the late daimyo of the Kozuki Family, Kozuki Oden. He ended up on Punk Hazard after stowing away on a ship. He was first mentioned when Kin'emon told Sanji that he came to Punk Hazard to rescue his "son". His given name was revealed when the samurai was asking if the captive children in the Biscuits Room had seen him, and the clan name revealed when Kin'emon spoke of the child's true heritage.