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It is voiced by Atushi Yanaka.
The Rider World was created when Asmodeus combined the records of the Kamen Riders with a Tojiru Gear. He was sent by Asmodeus, along with the Sentai Megid, to lead a group of revived villains to go after Shotaro Ishinomori.
Though the collective Kamen Riders were sealed within him, the Rider World was confronted by a group of heroes led by Zenkaizer and beaten, freeing them all. Accompanied by a group of past heroes, Touma and Kaito went to confront Asmodeus and his army of revived villains. However, as the Sentai Megid and Rider World led the villains against the heroes, Asmodeus approached Shotaro and manipulated him into tearing up the drawings he had done of his creations, causing them to disappear from reality. Asmodeus was able to trap Touma, along with his friends and Shotaro, in the reality of the Kamen Rider Saber book. With all the heroes out of the way, Asmodeus celebrated the defeat of the heroes with the past villains while a combined fleet of Zangyack Battleships, Triangulars, Moraimarz and the Crisis Fortress laid waste to a city.
However, Touma convinced Shotaro to keep working on his ideas and managed to break out, confronting Asmodeus and his villains. Shotaro then drew Kamen Rider 1 and Akarenger, causing them to appear in real life and summon all the heroes who came after. As the massive army of Kamen Riders and Super Sentai fought Asmodeus's army of villains, the Rider World was destroyed by Kamen Rider 1 and Kamen Rider Blades.