This article is about a/an A.R. World (another rider's world) in Kamen Rider Decade.
Den-O Backdrop

The backdrop for the World of Den-O.

The World of Den-O (電王の世界 Den'ō no Sekai) is the version of reality in which Kamen Rider Den-O supposedly takes place. In reality, this is actually occurs in the main Kamen Rider universe where the origins of Kamen Riders are. The backdrop used to enter this world depicts the DenLiner moving across the sands of time, which Ryutaros doodles on later in the episode arc. Within this world, Tsukasa finds himself wearing a trenchcoat and bucket hat, the same clothing as the Past Man and given abilities similar to those of a Singularity Point. Daiki's treasure in this world is the DenLiner.

The World of Den-O arc coincides with theatrical release of Cho Kamen Rider Den-O & Decade Neo Generations: The Onigashima Warship, which takes place within the continuity of Decade like Kamen Rider Den-O: I'm Born! did with Den-O. And later Daiki returns to the World of Den-O to settle things with Reiji Kurosaki who transforms into Kamen Rider G Den-O in Episode Yellow: Treasure de End Pirates, part of Kamen Rider × Kamen Rider × Kamen Rider The Movie: Cho-Den-O Trilogy. His treasures are the pistol heirloom from the Kurosaki family and the Diend K-Touch which transforms him into a Complete Form.




In the novel reimagination of the Kamen Rider Decade TV series, Kamen Rider Decade: The World of Tsukasa Kadoya ~The Garden Inside the Lens~, the World of Den-O is, as one of the Nine Worlds, is just like in the TV series, the original world. Having already traveled to six worlds, the World of Den-O is the first of the three remaining worlds the Hikari Studio group, Tsukasa/Decade, Kaito/Diend, and Natsumi, explore during the novel.

Tsukasa’s clothes change into a doctor’s uniform as they arrive in Den-O's World. Tsukasa meets Ryotaro Nogami, but his Imagin friends are missing. Tsukasa agrees to help him find them. The Den-O characters feel very off-character as their characteristics are different. Momotaros comes off as rather polite compared to his jerkish and self-centered TV counterpart, and actually refers to people by their real names instead of snarky nicknames. The Final Form Ride remains the same, as Tsukasa turns Den-O into Momotaros.



  • Due to the world taking place in the main timeline. It is most likely is the home of All Riders instead of just Den-O and should also be known as Main World of Kamen Riders (仮面ライダーライダーの主な世界 Kamen Raidā no Omona Sekai).
    • However, various original world Riders did take part in the final Rider War (including several whom Tsukasa never visited an alternate-world version of); as well as the events of simultaneous film "Kamen Rider W: Begins Night" which allows for the interaction of Shotarou Hidari and Philip with Decade during the final Movie Wars crossover that resolves both movies.
    • It's actually also the same universe as Super Sentai, with the latter was originally just known as World of Shinkenger, until the actual name of the Sentai world revealed in the first Super Hero Taisen.


As the prime Kamen Rider reality, what the Hikari Studio called the "World of Den-O" would appear in the vast majority of Kamen Rider works as well as in Super Sentai and other Toei HeroIcon-crosswiki productions, this list only contains the World of Den-O in regards to the Hikari Studio's visit.