Minato Miharu is a supporting character in Kamen Rider × Kamen Rider Fourze & OOO: Movie War Mega Max and Kamen Rider Zi-O, he's a young man who works as Kamen Rider Aqua, a hero from the future. However, due to his cowardly nature, Greeed Poseidon possessed him as Kamen Rider Poseidon. In Kamen Rider Zi-O, he utilizes as a hero and arrive in 2019 to resolve the temporal anomaly caused by Swartz that threatened his timeline.