Sokou Wada (Liar Game, the upcoming Shin Ultraman film) as Will, the personal secretary of Hiden Intelligence's former president, Korenosuke Hiden. This Humagear wants a world where "Humagears can smile", and he also holds the secret of birth of Zero-One. Wada also expressed that he wanted to appear in the Kamen Rider franchise, and wasn't sure if he'll be casted. He's happy when he was cast in the film.
In the upcoming film, Aruto lost his powers to transform into Kamen Rider Zero-One thanks to the appearance of Another Zero-One. Using the MetsubouJinrai ForceRiser and the Rising Hopper Progrise Key, Aruto transforms into Kamen Rider 001. How did he appear in Zero-One's world? That is for us to find as Kamen Rider Reiwa The First Generation is set a for December 21st release.
[Source: Eiga, NicoNico via JEFusion, Daisuki Toku]