Michal Minato

Michal Minato (湊 ミハル, Minato Miharu) is a Kamen Rider from the future who originally became the heroic Kamen Rider Aqua (仮面ライダーアクア, Kamen Raidā Akua) and later Kamen Rider Poseidon (仮面ライダーポセイドン, Kamen Raidā Poseidon) whose Core Medals took control of him. He is also the movie-exclusive Rider(s) who appeared in the OOO section of the Movie War Mega Max film.

Michal Minato
Michal is a Kamen Rider from 40 years in the future. At an unknown time he gained the Aqua Driver and the Aqua Miraider to fight monsters that appeared in his time. Michal however is a timid guy who feels he can't be a Rider and is ironically afraid of water. Receiving the Poseidon Driver from the Kosei Kougami, Kougami believes that the Poseidon Driver can help Michal overcome his timidness and fear. After a mysterious black hole opened from the past after losing a battle as Poseidon, Michal was knocked out of transformation, and the Core Medals and Cell Medals from the past entered his body, resulting in a Greeed forming inside his body. Michal is overtaken by the Greeed, becoming the main antagonist of the OOO portion, Kamen Rider Poseidon.

After Kamen Rider Poseidon lost some of the Core Medals in his body to Eiji and Ankh, the Greeed splits apart with Michal, gaining his own body in the form of Kamen Rider Poseidon. Michal becomes the protagonist Kamen Rider Aqua using the Aqua Driver that he gained before. After Eiji told him how he gets stronger and understanding what is to be a Kamen Rider. He went back to the future after aiding OOO in defeating Kamen Rider Poseidon, to protect his time as a Kamen Rider.

During the final battle, he travelled back to the past, aiding the Seven Legendary Riders. Before that, he acquired the Super Core Medals and gave them to OOO before his and Fourze's battle against the Super Galaxy King.

Trivia

 * Aqua is designed to resemble Kamen Rider #1 and #2, only with a simpler design and is powered by water instead of wind.
 * Aqua's use of a Jet Ski and water theme could possibly be an homage to Sea Jetter Kaito, a super hero from a theme park show in Ishinomaki, which is also home to the Ishinomori Manga Museum.
 * Michal is the second Rider that turns from good to evil because of being possessed by an evil spirit to become another Rider. The first is Ryotaro Nogami.