Although still a child, Momonosuke Kozuki is a key figure in the Wano saga. As the son of Oden and thus legitimate heir to the throne of the Samurai Island, he was protected by the Red Sheaths and his figure alone is enough to inspire the warriors of his island to fight. see ONE PIECE chapter 1015.
In the last chapter of the manga Luffy was defeated and Kaido made the announcement. Most of the samurai were discouraged and it seemed to be over now. Only a few protagonists of ONE PIECE have remained true to their will to fight. It was therefore necessary for Momonosuke to intervene, who a few seconds earlier had heard Luffy's voice in his head.
Though in the water that ONE PIECE protagonist managed to speak to Momonosuke, told him that he would return to fight. Taking advantage of one of Bao Huang's amusements, Momonosuke spoke to the whole island of Luffy's words and thoughts and managed to revive the mood of his army. The child could then give one again big hand on the spiritual and mental frontas happened in Udon prison.
The first spoilers for ONE PIECE 1016 have now been published.