Masamune Dan

"There are no continues for those who die frozen in time. He is trapped in the moment of death... permanently."

- Masamune after killing Lovrica Bugster "The human known as Masamune Dan has ceased to exist. I am an existence with the powers of both Cronus and Gamedeus. The overseer of Kamen Rider Chronicle... and the True Final Boss."

- Masamune after absorbing the data of Gamedeus.

Masamune Dan is the founder of Genm Corp and primary antagonist of Kamen Rider Ex-Aid, having manipulated the events of the series to further his own goals.

Discovering the Bugster Virus
16 years ago, Masamune Dan learned of the existence of the Bugster Virus from his son, Kuroto Dan, who discovered it after it emerged from the Y2K crisis. Unbeknownst to everyone but himself, Masamune infected himself with the virus to develop an antibody for it within him.

After his son caused Zero Day and pinned the blame on him, Masamune willing took responsibility and allowed himself to be incarcerated in order to further his own goals, letting Kuroto step up to become CEO of Genm though, ubeknownst to him, his father was secretly using him to further his own goals.

Release
Masamune was eventually released from prison, allowing him to retake control of the Genm Corp. He soon showed his true colors to the Kamen Riders, revealing that his incarceration and Kuroto's succession of him had all been part of his plan.

Masamune blackmailed Hiiro into turning to his side with Proto Drago Knight Hunter Z, which had his girlfriend, Saki Momose, sealed inside of it. After much reluctance, Hiiro accepted the offer and betrayed Emu and Kuroto and prevented them stopping the Pause ability of Cronus.

With Hiiro's assistance, Masamune revived Kiriya, so he could become observant for the players of Kamen Rider Chronicle and prevent the doctors from stopping its progress. However, reviving Kiriya turned out to be Masamune's biggest mistake, as Kiriya revealed that his true purpose was to make an opening so Emu and Kuroto would create a new way to defeat him.

Cronus was later defeated by Ex-Aid Muteki Gamer. Angry at his defeat, Masamune forced Hiiro to control Taddle Legacy, threatening to kill Saki for good.

Final Battle
Following the failure of his scheme to use Gamedeus to instigate another global pandemic, Masamune finishes off Gamedeus and absorbs his remains into his body, turning himself into Gamedeus Cronus. However, the Riders all revert back to Level 1, allowing them to separate Masamune and Gamedeus, with Parado sacrificing himself to destroy the latter with the Doctor Mighty XX Gashat.

Masamune then fights against the Riders as Cronus. While holding his own at first, Cronus ends up being overwhelmed by the Riders once they switch to their Level 2 forms, with Emu delivering the final blow. However, to prevent any of the eliminated players from being saved, Masamune kills himself out of spite.

Personality
Though he keeps up the guise of a friendly and benevolent businessman, Masamune's true personality underneath is that of a self-centered sociopath and manipulator who cares for nothing but his own goals, being willing to kill thousands of people in order to achieve them. He addresses each of the Kamen Riders and Bugsters by the Rider Gashats they use or in the game they originated from, viewing them not as living beings but as products of the Genm Corp and even refers to killing them off as "discontinuing a product".

For the first half of the series, Masamune keeps up the facade of a well-meaning CEO and father while he is behind bars and Kamen Rider Chronicle is in development. However, after he is released from jail and his plans start to come to fruition, Masamune reveals himself to be a tyrannical control freak who believes he has the right to control everyone's fates and is willing to do whatever it takes to see the end result of his goals, including resorting to underhanded and deceitful tactics.

Even after he has been defeated, Masamune clings to his belief that he is the controller of everyone's lives, and kills himself purely out of spite to preventing the victims of Kamen Rider Chronicle from being saved.

In Another Ending trilogy, it is revealed that Masamune was once a loving man who genuiely cared about his wife, before he turned insane because of her infection of Bugster virus.