Akumaizer

The evil Akumaizer (アクマイザー) are the main antagonists, residents of the Underworld who are seen by humans as "devils" (悪魔). They revive the Dopants, Yummy, Zodiarts, and Phantoms that were previously defeated by the Kamen Riders to make an Monster Army (怪人軍団) to invade and conquer humanity. The Akumaizer are a homage to the protagonists of Akumaizer 3, which was also created by Shotaro Ishinomori.

Xatan
Xatan (ザタン) is the leader of the Akumaizer who is able to use the Underworld's magic. He plans on taking over the world together with his subordinates Eel and Gahra.

Xatan is a homage to Xavitan from Akumaizer 3, who is also the leader of the team.

Xatan is voiced by Demon Kakka (デーモン閣下) of Seikima-II.

Eel
Eel (イール) is the most agile and skilled fighter of the Akumaizer, skilled in aerial combat.

Eel is a homage to Evil from Akumaizer 3.

Eel is voiced by Tomokazu Seki (関 智一).

Gahra
Gahra (ガーラ) is the strongest of the Akumaizer. He has a large, muscular physique and has superhuman strength.

Gahra is a homage to Gabra from Akumaizer 3.