
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.

as Gentaro Kisaragi / Kamen Rider Fourze

as Eiji Hino / Kamen Rider OOO

as Shotaro Hidari / Kamen Rider W / Kamen Rider Joker

as Philip / Kamen Rider W

as Ankh

as Nadeshiko Misaki / Kamen Rider Nadeshiko

as Kamen Rider 1 (voice)

as Kamen Rider 2 (voice)

as Kamen Rider V3 (voice)

as Riderman (voice)

as Kamen Rider X (voice)

as Kamen Rider Amazon (voice)

as Kamen Rider Stronger (voice)

as Hina Izumi

as Chiyoko Shiraishi

as Erika Satonaka

as Akira Date / Kamen Rider Proto-Birth

as Shintaro Goto / Kamen Rider Birth

as Birth Driver (voice) / Birth Buster (voice)

as O Scanner (voice) / Poseidon Driver (voice) / GingaOh Driver (voice)

as Kamen Rider Poseidon (voice)

as Miharu Minato / Kamen Rider Aqua

as Kōsei Kōgami

as Gaia Memory (voice)

as Katal

as Solaris

as Chancellor Kiima

as Lem Kannagi

as Kengo Utahoshi

as Yūki Jōjima

as Shun Daimonji

as Miu Kazashiro

as Tomoko Nozama

as JK

as Chūta Ōsugi

as Mitsuaki Gamō

as Virgo Zodiarts (voice)

as Mysterious student