Movie War Mega Max featured the first seven Kamen Riders (Kamen Rider 1, 2, V3, Riderman, X, Amazon, and Stronger) to commemorate the franchise's 40th anniversary. Trailers for the film shown during airings of Fourze also showed the return of Kamen Rider Double as well as a new form for Kamen Rider OOO. Unlike previous Movie War films, where they were divided into 3 segments, Movie War Mega Max is divided into 5 parts. Like previous Movie War films the secondary Kamen Rider of Kamen Rider Fourze, Kamen Rider Meteor, made his debut in the film.
渡部秀
as Eiji Hino / Kamen Rider OOO
三浦涼介
as Ankh
福士蒼汰
as Gentaro Kisaragi / Kamen Rider Fourze
真野恵里菜
as Nadeshiko Misaki / Kamen Rider Nadeshiko
桐山漣
as Shotaro Hidari / Kamen Rider Joker
稲田徹
as Kamen Rider 1 (voice)
藤本たかひろ
as Kamen Rider 2 (voice)
田中大文
as Kamen Rider V3 (voice)
Takayuki Masuda
as Riderman (voice)
千葉一伸
as Kamen Rider X (voice)
Koji Tobe
as Kamen Rider Amazon (voice)
石川英郎
as Kamen Rider Stronger (voice)
