Kozuki Momonosuke

Momonosuke is the son of Kinemon. In the end of Chapter 682, a little girl mentions "he went into the 'Secret Room' you're not supposed to go into. That boy, Momonosuke, that changed into a little dragon!"

History
He was first mentioned when Kinemon told Sanji that he came to Punk Hazard to save his son. His name was revealed when the samurai was asking if the giant children in the Biscuits Room had seen him.