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.
Shu Watanabe
Eiji Hino / Kamen Rider OOO
Ryosuke Miura
Ankh
Sota Fukushi
Gentaro Kisaragi / Kamen Rider Fourze
Erina Mano
Nadeshiko Misaki / Kamen Rider Nadeshiko
Renn Kiriyama
Shotaro Hidari / Kamen Rider Joker
Tetsu Inada
Kamen Rider 1 (voice)
Takahiro Fujimoto
Kamen Rider 2 (voice)
Hirofumi Tanaka
Kamen Rider V3 (voice)
Takayuki Masuda
Riderman (voice)
Isshin Chiba
Kamen Rider X (voice)
Hideo Ishikawa
Kamen Rider Stronger (voice)
Riho Takada
Hina Izumi
Mayuko Arisue
Erika Satonaka
Hiroaki Iwanaga
Akira Date / Kamen Rider Proto-Birth
Asaya Kimijima
Shintaro Goto / Kamen Rider Birth
Jouji Nakata
Birth Driver (voice) / Birth Buster (voice)
Akira Kushida
O Scanner (voice) / Poseidon Driver (voice) / GingaOh Driver (voice)
Kenji Hamada
Kamen Rider Poseidon (voice)
Atsushi Arai
Miharu Minato / Kamen Rider Aqua
Takashi Ukaji
Kōsei Kōgami
Masaki Suda
Philip / Kamen Rider Double
Fumihiko Tachiki
Gaia Memory (voice)
Sanae Hitomi
Solaris
Toru Masuoka
Lem Kannagi
Ryuki Takahashi
Kengo Utahoshi
Yoshiko Sengen
Yūki Jōjima
Justin Tomimori
Shun Daimonji
Rikako Sakata
Miu Kazashiro
Shiho
Tomoko Nozama
Shion Tsuchiya
JK
Takushi Tanaka
Chūta Ōsugi
Shingo Tsurumi
Mitsuaki Gamō
Rie Tanaka
Virgo Zodiarts (voice)
Ryo Yoshizawa
Mysterious student
