This article is about a/an rider in Kamen Rider Agito.

Shiro Mizuki (水城 史朗 Mizuki Shiro) is a soldier who becomes Kamen Rider G4 (仮面ライダーG4 Kamen Raidā Jī Fō, Masked Rider G4).


He was one of the military personnel guarding the GA psychic educational facility during the time it was attacked by the Formica Pedes. Though he would survive the ordeal, he would be left a jaded man.

With his pride as a soldier shattered, Mizuki began living as one who would embrace death as the true means of becoming stronger. He would eventually volunteer as the operator for the G4 exo-suit and, as fate would have it, clash with G3-X operator Hikawa, to put their ideals to the test on the battlefield. But throughout the course of the battle, the G4 begins to suffer malfunctions.

Despite this, Mizuki refused to surrender. In the end, Mizuki would succumb to the strain placed upon him by the G4 and die. The G4's AI attempted to rise and continue the battle, but was destroyed by Hikawa.


01.Rider War

Video Game appearances

Kamen Rider Agito video game

In the Kamen Rider Agito game for the Playstation, while G3/G3-X has limited fighting time and will instantly K.O after the time is over, G4 doesn't suffer that limitation, possibly because G4 is a more advanced version and has successfully eliminated the weakness of G3/G3-X system.

Kamen Rider Battride War II


G4 in Kamen Rider Battride Wars II.

G4 reappeared in Kamen Rider: Battride War II as a boss fighting against. Kamen Rider Agito and Kamen Rider G3-X

Kamen Rider Battle Rush

Kamen Rider G4 appears as a playable and support character in the video game Kamen Rider Battle Rush using Gigant.

Kamen Rider Buttobasoul


Kamen Rider G4 is a playable character in Kamen Rider Buttobasoul.

Kamen Rider G4

Kamen Rider G4

Kamen Rider G4

Rider Statistics

  • Rider Height: 198 cm
  • Rider Weight: 150 kg

Ability Parameters:

  • Punching Power: 4 t
  • Kicking Power: 13 t
  • Maximum Jump Height: 25 m
  • Maximum Running Speed: 100 m per 7.5 seconds

Generation 4 is the successor to the G3 system. It was conceptualized by Sumiko Ozawa based G3-X. However, the system was deemed far too dangerous for use, so Ozawa never included the adjustments in the design schematics. However, Risako Fukami would steal the plans and construct the G4 System herself, adding a Prediction System to improve the AI. Unlike G3, the design of which was based on Kuuga, G4 is based on Agito. G4 is much stronger than any iteration of G3. However, its advanced AI causes it to suffer similar issues to G3-X

This Rider is exclusive to Kamen Rider Agito: Project G4.


  • GM-01 R4 - A modified version of the Kamen Rider G3's GM-01 "Scorpion"; a modular magnum pistol, stored on right hip, hand-carried in use.
  • Gigant - A shoulder-mounted missile launcher, mounted over the right shoulder when in use. Used as a finisher.

Rider Cards

Kamen Ride G4

Kamen Ride: G4

G4 in Episode Yellow

G4 as summoned by Diend Complete Form.

Behind the scenes


Shiro Mizuki was portrayed by Ryo Karato (唐渡 亮 Karato Ryō). As Kamen Rider G4, his suit actor was Jiro Okamoto (岡元 次郎 Okamoto Jirō).


  • G4 can be considered the first movie-exclusive Kamen Rider of the Heisei era.
  • In terms of the users (Hikawa and Mizuki), the utilization of the G3-X and the G4 exo-suit near the end of Project G4 is reminiscent of the final battle between Kuuga Ultimate Form and N-Daguva-Zeba.
    • Shiro Mizuki and N-Daguva-Zeba also happen to be more willing to die (and end up doing so) for their motives, with Mizuki fighting for his ideals in life, and N-Daguva-Zeba fighting to accomplish either one of his goals.
  • Unlike the majority of Heisei Dark Riders, who are counterparts with the Primary Rider of their respective series, G4's counterpart is the Secondary Rider G3-X, despite his armor being based on Agito.

G4-chip in Kamen Rider Decade


See Also

Icon-agito Kamen Rider Agito
Kamen Riders
Shouichi Tsugami - Makoto Hikawa - Ryo Ashihara - Kaoru Kino - Shiro Mizuki (Movie Exclusive)
Mana Kazaya - Professor Yoshihiko Misugi - Taichi Misugi - Dr. Higashi Kunieda
Tokyo Police Department
SAUL Team: Sumiko Ozawa - Takahiro Omuro
Police: Toru Hojo
The Akatsuki Survivors
Tomoko Miura - Saeko Shinohara - Aki Sakaki - Katsuhiko Sagara - Masumi Sekiya - Koji Majima - Jun Tachibana - Masahide Takashima - Kazuo Ashihara
The Lords
The Els: El of the Water - El of the Wind - El of the Ground
Jaguar Lords - Tortoise Lords - Snake Lords - Crow Lords - Zebra Lords -Jackal Lords - Bee Lords - Stingray Lords - Fish Lords - Lizard Lords - Ant Lords
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