Kuroto Dan

"Do not talk back to the game master! Both Emu Hojo and Tsukuru Koboshi made a new Gashat without my permission. How dare they create their own Gashats! Gashats are a product of my mind! It should be something only I can make! The same goes for you Bugsters. You're nothing but pawns, useful tools to make my plans a reality. I designed game characters from scratch. Designed their thought processes, controlling them as I will. I am the game master! I am God!"

- Kuroto Dan's rant.

Kuroto Dan is the CEO of the Genm Corp and one of the main antagonists of Kamen Rider Ex-Aid alongside Parado and Masamune Dan. He is capable of using his Gamer Driver to become Kamen Rider Genm. He serves as the main antagonist of the first half of the series and a supporting anti-hero in the series' second half and True Ending movie. In Another Ending trilogy, Kuroto returns back to villainy and serves as the trilogy's overall main antagonist.

His ultimate goal is to trap everyone in the game Kamen Rider Chronicle, where humans and Bugsters will be forced to fight it out as a testament to his genius. However, Kuroto secretly plans to use the game to bring back his mother. Should the human side win, all those who have vanished will be revived, including his mother.

He was portrayed by Tetsuya Iwanaga.

Origin
At 14 years old, Kuroto was a game developer for the Genm Corp, having created numerous successful games.

One day, Kuroto received a fan mail from Emu Hojo suggesting a new idea for a game. Though impressed, Kuroto was angered that someone else was as talented as him and thus he sent him a game called Mighty Action C that contained the Bugster Virus. When Emu played it, he became infected with the virus.

Zero Day
In 2010, Kuroto hired the Next Genome Institute to abduct Emu after the Bugster virus within him fully matured, with Kuroto having secretly observed the virus' development for the past decade.

With the virus now in his hands, Kuroto used it to trigger Zero Day, where the Bugsters emerged from the glitches of 10 games produced by the Genm Corp. In collaboration with the Ministry of Health, Kuroto designed the Gashats and Gamer Driver to counter the Bugsters.

Kuroto managed to avoid punishment for the outbreak by framing his father Masamune Dan for it. With his father out of the way, Kuroto became CEO of Genm Corp.

Second Bugster Outbreak
A second Bugsters outbreak occurred following the release of Genm Corp's new game, Mighty Action X. Unbeknownst to everyone, Kuroto was secretly collaborating with the Bugsters, needing their help to develop his ultimate masterpiece, Kamen Rider Chronicle, a game where people in the real world would be forced to fight against Bugsters for his amusement.

However, he is betrayed by Parado, who steals his Gashacon Bugvisor and uses it to infect him with the Dangerous Zombie Gashat. As Kuroto disintegrates, Parado announces that Kamen Rider Chronicle now belongs to him.

Return
He was later brought back by Poppy, who needed his assistance to complete Kamen Rider Chronicle. Though brought back as a Bugster, Kuroto was gleeful that he had achieved immortality. Kuroto then transforms into Genm Level 0 head to the Next Genome Institute to get revenge on Parado. He attacks Parado just as he is about to finish off Emu, saving the heroic Rider in the process.

Kuroto later attempts to threaten the doctor Riders once they're back at CR, but Poppy absorbs him back into the Bugvisor II.

War against Masamune Dan
Once his father stepped into the picture and hijacked Kamen Rider Chronicle for his own plans, Kuroto was forced to stayed aligned with Emu and co. to stop him. He collaborated with Kiriya Kujo to develop a vaccine for the Gamedeus Virus. with the data they had gathered from fighting each other, Kuroto was able to create the Doctor Mighty Double X Gashat, which Emu could use to cure people of the Gamedeus Virus.

However, after the cure was finished development Kuroto was handed over the Ministry of Health by Poppy and Kiriya, though because of his role in developing the cure Kuroto only received a light sentence of house arrest.

Final Battle
Kuroto later discovered that Poppy had sacrificed herself to cure Super Gamedeus' horde. A distraught Kuroto was comforted by Poppy who told him not to cause trouble and to keep making games before fading.

As Zombie Action Gamer, Kuroto fought alongside Ex-Aid and the other Riders against Super Gamedeus. Though they were initially unable to do anything, Kuroto figured out that they could separate Masamune from Gamedeus by reverting back to Level 1. After Gamedeus was neutralized by Doctor Mighty XX and Parado's sacrifice, Kuroto as Zombie Action Gamer fought Cronus, but was ultimately beaten down by his father. However, Cronus was then overpowered by Ex-Aid, who revealed that Cronus had been weakened by Parado's sacrifice. Switching to Level 0, Kuroto joined the other Riders in fighting Cronus and together they were able to defeat him. In one last act of spite, Masamune killed himself to prevent any of the Game Disease victims from being revived.

Aftermath
Kuroto later managed to revive Poppy from the sample of her virus that he had absorbed into his hand. He also revealed to Emu that he had been infected with a fragment of Parado, which was why he could still transform into Ex Aid. Parado then returned from within Emu right after.

Kuroto later created a new game called Kamen Rider Build and revealed it to Poppy, Parado and Emu, allowing Emu to test its Gashat.

Kamen Rider Ex-Aid: Another Ending Trilogy
However, Kuroto soon went back to his old tricks, teaming up with Saiko Yaotome and the Next Genome Institute and attempting to trap everyone in his new zombie apocalypse war game, Zombie Chronicle.

Personality
Though appearing as a polite and affable man to the public, Kuroto is a psychotic and malignant individual who cares little about anyone not himself, including his own father whom he was willing to frame and get thrown in jail. He displays many traits of narcissism, having an inflated opinion of himself and viewing himself as a god. He is prone to immense rages when something is introduced to his game that is not of his design and derives a sadistic glee from murdering people for small slights.

However, Kuroto also holds a genuine love for his mother, as well as Poppy, being an entity partially spawned from his mother.

Trivia

 * Ironically, while Kuroto is the cause of the Bugster Virus in the show, his actor Tetsuya Iwanaga is a licensed pharmacist.
 * Dan's hamminess and exaggerated facial expressions have made him one of most memetic Kamen Rider characters.