This article is about a/an villain in Kamen Rider Ex-Aid and Kamen Rider Ghost.

Michihiko Zaizen (財前 美智彦 Zaizen Michihiko), also known as Dr. Pac-Man (DR.パックマン Dokutā Pakkuman), was a villain in Kamen Rider Heisei Generations: Dr. Pac-Man vs. Ex-Aid & Ghost with Legend Riders. He was the leader of Next Genome Institute who brings forth a new Bugster Virus strain based on the famous video game character, Pac-Man. After having the Hatena Bugster mutate him by rewriting his genetic makeup to become a combination of Bugster and human DNA, he can become the Genomes (ゲノムス Genomusu).

Character History

Early Life

He, along with the other members of the Next Genome Institute, operated on Emu Hojo to spread the Bugster virus, on the request of Kuroto Dan. However, a large amount of the Bugster virus was released, infecting the group of surgeons and causing them to vanish in an instant. A New Challenger Appears!

Heisei Generations: Dr. Pac-Man vs. Ex-Aid & Ghost with Legend Riders

At some point in time, the members of the Institute were revived as Bugsters. In the present, while assuming the identity of "Dr. Pac-Man", Zaizen created a new type of virus known as the Pac-Man Virus, in order to locate the strain of a new type of Bugster virus, which turned out to be hosted within Togo Kiyomiya, a high school student who is also the creator of the game Hatesate Puzzle. The virus from Togo spawned into the Hatena Bugster.

Using the Hatena Bugster's power to rewrite his DNA, Zaizen completed his plan of evolving himself into a more powerful being known as the Genomes. He also attempted to evolve Togo into a similar being, using the Gashacon Bugvisor stolen from Genm Corp., and had planned to mass produce the treatment once the experiment on Togo was complete.

Genomes would ultimately be destroyed by Kamen Rider Ex-Aid Double Action Gamer Level XX's Critical Strike. Kamen Rider Heisei Generations: Dr. Pac-Man vs. Ex-Aid & Ghost with Legend Riders


Following Zaizen's downfall, the alias of "Dr. Pac-Man" would be taken by Parado as he interrupted Kuroto Dan's own plot to utilize the Ganbarizing Gashat as part of a game in which he provided Bandai Namco-based Gashats to the doctor Kamen Riders. Kamen Rider Ex-Aid "Tricks": Kamen Rider Genm

Dr Pac-Man holding the three Legend Gamer Gashats

"Dr. Pac-Man" returns, holding three legendary Gashats.

Admitting to Taiga Hanaya that Emu Hojo was patient zero of the Game Illness, Kuroto Dan claimed that he was given it six years ago in an experiment conducted by Michihiko Zaizen. A New Challenger Appears! He neglected to mention, however, that it was he himself who first gave him the Bugster Virus a further decade prior, and that Zaizen merely extracted the cultivated virus. Dan would later confess to Emu that he had ordered Zaizen to extract the matured virus from him.Engineered History! Said virus is later revealed to be Parado. We're Me!?

Dr. Pac-Man data

Returned as data copy by his own daughter.

His data was later used by his daughter, Saiko Yaotome, to reproduce a copy of Genomes in order to battle with Another Parado against Kamen Riders Para-DX and Poppy. Kamen Rider Para-DX with Poppy


to be added

Powers and Abilities

to be added


Genomes Bugster High Quality



Behind the scenes


Michihiko Zaizen & Dr. Pac-Man was portrayed by Shiro Sano (佐野 史郎 Sano Shiro), who previously played Weeval/Makuu Prison Warden AshuradaIcon-crosswiki in Kaizoku Sentai Gokaiger vs. Uchuu Keiji Gavan: The MovieIcon-crosswiki. As Genomes, his suit actor is unknown.


  • Michihiko Zaizen is the third character who uses the Gashacon Bugvisor, and the second Bugster to use it as a weapon.
    • Unlike Graphite and Lovelica, he doesn't use it to transform, but still uses it for its other functions, including infecting his targets like Graphite did.
  • Genomes is designed by Niθ.