Jinpei and his friends will participate in "IKUSA", a fighting competition held at the high school. In order to win the battle, that person appears, to all the people who want to improve their hero's power. The power-up method presented by Master Zazel is to pull out the Classic Yo-kai from the new Yo-kai World from within Earth Walker and perform an "initiator union". Jinpei and his friends, who are handed Majin Watches made by Kuka, are given special training. For some reason, only Fubuki couldn't get help from Mermaidyn while the people around her became Initiator Yo-kai Heroes one after another.
