This article is about a/an monster in Kamen Rider Ex-Aid.
Series: Kamen Rider Ex-Aid
Villain Type: Boss
Affiliation: Bugsters
Homeworld: Kamen Rider Chronicle
Actor: TBA

"Gemdeus is an almighty god that is even more powerful than every game combined. When all game clear tokens are collected, Gemdeus will descend upon this world."
Kuroto Dan explains about the Kamen Rider Chronicle's final boss to Emu and the others[src]

―Gemdeus' proclamation[src]

Gemdeus (ゲムデウス Gemudeusu) is the thirteenth and final boss Bugster of Kamen Rider Chronicle. As per the rules of the game, the Ride-Player who has defeated and claimed the Gashatrophies of the twelve Bugster bosses will be able to challenge Gemdeus as the final boss of the game. No other data exists about it other than it being conceived by Kuroto Dan.

Character History



Silhouette of Gemdeus

While acting as navigator for a group of human Ride-Players, Poppy revealed the existence of the game's final boss, describing it as the final challenge to be faced by the Ride-Player who manages to defeat the twelve familiar Bugsters and claim their Gashatrophies. Start the New Game!

Entrusted to beat Kamen Rider Chronicle by Emu, Nico Saiba realized that she would have to defeat Parado before facing the final boss, encouraging Taiga Hanaya to accompany her in confronting him. Strongest VS Strongest!

According to Kuroto Dan, Gemdeus is the ultimate Bugster, transcending the power of any and all games. The only way to defeat Gemdeus is to obtain the power of Kamen Rider Cronus.

As theorized by Parado, since Cronus is the only one who can stop Gemdeus, Gemdeus would also have the power to stop Cronus as well, though Kuroto himself had assumed that Cronus could not be defeated via conventional means. With that in mind, Parado and Graphite went into the game world of Kamen Rider Chronicle to collect Gemdeus' virus data from the silver-colored Bugster Union form of Gemdeus. In an attempt to replicate the virus data, Graphite injected the virus into himself, but the power proved too much for him to handle. As Parado and Graphite faced Cronus yet again, Graphite transmitted the virus into Cronus' Buggle Driver II, which rendered the Pause ability useless. However, Lazer Turbo made his appearance and neutralized the virus within the driver. Accomplished Rebirth!

Graphite grew visibly ill as the Gemdeus virus multiplied within his body. He accepted his pain, however, as the price it would take to defeat Cronus and take back Kamen Rider Chronicle. Rescue the Partner!

Powers and Abilities

  • Godlike Powers: As the final boss of Kamen Rider Chronicle, Gemdeus possess the greatest power of all Bugsters.
    • Virus Cultivation: In its Bugster Union form, Bugster Viruses containing Gemdeus' data is generated on its body. These viruses can cause extreme pain and white flames on most Bugsters who contain this virus. It can also suppress certain abilities of Kamen Rider Cronus such as the Pause function.


  • Kamen Rider Cronus: As the symbol that was designated to go against Gemdeus. Cronus is one of the few riders who logically can defeat Gemdeus.
    • Pause: The key ability exclusively for Cronus to defeat Gemdeus. It can stop the flow of time around Cronus. It is also used to prevent any defeated Bugsters to be revived.
  • Level 0 Gashats: Bugsters who are in the Game Areas created from Level 0 Gashats will have certain abilities restricted. In Gemdeus' case its cultivation is suppressed by erasing it's virus. Even if the virus is in any Gashacon Bugvisors, it can still be erased by touching the visor. Also, any attacks with the usage of Level 0 Gashats can effectively damage Bugsters, regardless of their level gap.


Bugster (Bacteria)

Bugster Virus bacterium.

The Bugsters originate as the microscopic Bugster Virus (バグスターウイルス Bagusutā Uirusu), a result of humans being contaminated by the Bugster, thus developing the condition known as the Game Disease (ゲーム病 Gēmu-byō).

Gemdeus Union

Gemdeus' Bugster Union form.

Appearances: Ex-Aid Episode 34

Screenshot 20170611-093316



  • Gemdeus comes from the words Game and Deus. While Gem and Game sounds similar, Deus is a Latin word which means God. So a literal translation of Gemdeus's name would be "Game God".
  • Being designed as a final boss, Gemdeus' design and color schemes are mostly based on Bat Fangire and Over Lord Inves Lord Baron, with a similar design bases as Megahex's first form.



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