- Comedian Shohei Osada (Sin Clock) as Mera, a man from the future who is responsible for the "World Doomsday Game". He also transforms into the jet black Rider, Kamen Rider X-Geats!
- Haruka Kudo (Kaitou Sentai Lupinranger vs. Keisatsu Sentai Patranger) as Mero, a woman from the future who is also responsible for the "World Doomsday Game".
Because of the "World Doomsday Game" started by Mera and Melo, the world is divided into four and Ace is also split into four people with different personalities! Kamen Riders Keilow, Lopo, and PunkJack rush in, but the strongest player in history, X-Geats stands in their way! What will be the fate of Ace and the world?!
Written by series head writer Yuya Takahashi, and directed by Shojiro Nakazawa (Kamen Rider Ex-Aid: True Ending), Kamen Rider Geats the Movie: 4 Aces and the Black Fox is set to premiere this July 28th, and is double-billed with Ohsama Sentai King-Ohger the Movie: Adventure Heaven.