The Underground Empire Badan makes its move, intending to invert the world. Kouta and Mai are pulled through one of these inversions where the discover a boy named Shu, who also holds the power to invert the world. As the Riders fight to protect Shu, Fifteen appears again, seeking Shu. As Kouta flees, past Riders gather and fight one another, split between the Showa and Heisei era Riders. But, the truth of Badan is not as it seems…
Gaku Sano
Kouta Kazuraba / Kamen Rider Gaim
Hiroshi Fujioka
Takeshi Hongo / Kamen Rider #1
Itsuji Itao
Ren Aoi / Kamen Rider Fifteen
Masahiro Inoue
Tsukasa Kadoya / Kamen Rider Decade
Kento Handa
Takumi Inui / Kamen Rider Faiz, Riderman (voice)
Renn Kiriyama
Shotaro Hidari / Kamen Rider Joker / Kamen Rider Double
Yutaka Kobayashi
Kaito Kumon / Kamen Rider Baron
Mahiro Takasugi
Mitsuzane Kureshima / Kamen Rider Ryugen
