Gamedeus

Gamedeus (ゲムデウス) 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 Gamedeus as the final boss of the game.

Foreshadowing
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.

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.

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

As theorized by Parado, since Cronus is the only one who can stop Gamedeus, Gamedeus 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 Gamedeus' virus data from the silver-colored Bugster Union form of Gamedeus. 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.

Graphite grew visibly ill as the Gamedeus 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. Indeed, Graphite was able to use the Gamedeus virus to successfully block Cronus' ability to pause in their next engagement, however, Cronus retained the advantage by seizing control of all Energy Items.

Portrayal
Gamedeus is voiced by Masashi Sugawara (菅原 正志).