Yonji has been described as callous and stingy, refusing to help a dying Luffy and challenging the Straw Hats to plunder the Germa 66 ship for the cure for Luffy's condition. His elder sister, Reiju, claimed that he was rotten to the core. Yonji seems to take amusement in instigating or observing conflict, as he offered to lead Sanji to Niji for a fight with a smile and acted similarly when he tried to goad the Straw Hats into attacking him. He is also proud, getting angry at Reiju