This article is about a/an alternate reality/A.R. World (another rider's world) in Kamen Rider Decade.
For a history of this reality, see Timeline.
Kamen Rider Prime World


According to several sources, the World of Kamen Rider (仮面ライダーの世界 Kamen Raidā no Sekai) is the prime universe containing the Earth which is home to the vast majority of Kamen Riders. It is evidently from this reality that alternative A.R. Worlds are derived.

The prime Eiji Hino was said to inhabit the World of Tatoba (タトバの世界 Tatoba no Sekai), one of several worlds home to different incarnations of Kamen Rider OOO. Kamen Rider OOO: Final Stage

Frey, a humanoid avatar of the extra-terrestrial Great Eye, refered to this Earth as Takeru's World (タケルの世界 Takeru no Sekai) in reference to Takeru Tenkuji. Drive Chapter

In reference to the Bugster who was stranded in the World of Build, the people he met in that world initially refered to his home as Parado's World (パラドの世界 Parado no Sekai). Kamen Rider Heisei Generations FINAL: Build & Ex-Aid with Legend Riders

Known universe

Miscellaneous dimensions

Behind the scenes


Showa Rider

Since the original series was directly followed by Kamen Rider V3, the Showa era consistently depicted the successive Kamen Rider Series as taking place in the same world, culminating with the appearance of the first ten Kamen Riders in the final episodes of Kamen Rider Black RX. It is noted, however, that Kamen Rider (Skyrider) and Kamen Rider Black were both conceived initially as "reimaginings" of Kamen Rider, only to reintroduce previous Kamen Riders.

In the 1990s, the output of the live-action Kamen Rider Series consisted of three feature-length films: Shin: Kamen Rider Prologue, Kamen Rider ZO, Kamen Rider J. As further attempts to reimagine Kamen Rider to a contemporary setting, each film was a standalone feature with their own independent stories. Despite this, however, the short film Kamen Rider World united the heroes of ZO and J while featuring a horde of their revived enemies, including the monster from Shin, led by Shadow Moon of Kamen Rider Black. By association, this crossover placed all Showa Riders in the same world.

Heisei Rider Phase 1

The Kamen Rider universe became complicated, however, following the franchise's returned to TV in the Heisei era. The first new series, Kamen Rider Kuuga, though loosely recalling the original Kamen Rider in the form of a Professor Hongo, features an distinct Rider and lore with no explicit connections to past series. Barring a brief attempt to tie the subsequent Kamen Rider Agito to Kuuga, an apocryphal crossover between Kamen Rider Ryuki and Agito, and a feature length crossover between Den-O and Kiva, the first nine series remained generally standalone.

Kamen Rider Decade, the 10th anniversary series of Heisei Rider, introduced the concept of a Kamen Rider multiverse. Though the eponymous Rider traveled to worlds derived from the past Kamen Rider Series, these were alternative realities to their original series; though certain past characters did appear in their original forms, their settings were not touched upon.

Heisei Rider Phase 2

Following Decade came the second phase of the Heisei era, starting with Kamen Rider W. Connecting W to Decade, Movie War 2010 began a regular series of Kamen Rider crossovers. As well as that, a tradition soon began of introducing characters from the upcoming series within the Summer Movie, which was otherwise dedicated to the incumbent; in other cases, future characters would be introduced in the concluding episodes of the preceeding series.

These frequent crossovers served to establish W and its successors as sharing a common world. As well as that, the Showa Riders and indeed the previous Heisei Riders were incorporated into these crossovers as well. As such, the vast majority of Kamen Rider Series live-action works are treated as taking place in the same universe.

Distinctly, the TV series Kamen Rider Build as well as the Amazon Prime series Kamen Rider Amazons, are noted as taking place in their own distinct realities. However, in the former's final episode, Build's own universe is merged with the main continuity's reality, resulting the creation of a "new world", with the two Riders from the said universe being the survivors from their old world.

The final Heisei Rider series, Kamen Rider Zi-O, retroactively explains each past Rider series as belonging to its own world, thereby retconning crossovers between Riders as a result of mergers between worlds.

Kamen Rider's World

The 2012 film Super Hero Taisen first made reference to the Rider World (ライダ一界 Raidā Kai), which used by Doktor G as the name for the home of Dai-Shocker, the union of evil organizations as introduced to the Go-Busters. Material related to the movie also uses the names Kamen Rider World (仮面ライダ一界 (仮面ライダー世界) Kamen Raidā Kai (Kamen Raidā Sekai)) to describe this version of reality where all the Kamen Rider TV shows take place. While explicitly featuring the settings of contemporary shows Kamen Rider Fourze and Tokumei Sentai Go-BustersIcon-crosswiki, the movie itself does not specify where the action is taking place most of the time, but it does feature characters going from one location to another through Kamen Rider Decade's dimensional walls.

The World of Kamen Rider (仮面ライダーの世界 Kamen Raidā no Sekai) was later used in Shuriken Sentai Ninninger Vs. Kamen Rider Drive Spring Vacation Combining Special (2015) by Kyuemon IzayoiIcon-crosswiki to refer to the Kamen Riders' prime reality where the characters from Shuriken Sentai NinningerIcon-crosswiki temporarily cross into due to the History Modifying Machine altering reality.

In the non-narrative introduction to Kamen Rider × Super Sentai: Chou Super Hero Taisen: Movie Release Anniversary Special (2017), Takumi KizuIcon-crosswiki (LuckyIcon-crosswiki) notes KyurangerIcon-crosswiki as visiting the World of Kamen Rider Ex-Aid (仮面ライダーエグゼイドの世界 Kamen Raidā Eguzeido no Sekai). Indeed, the interdimensional properties of Ex-Aid's KyutamaIcon-crosswiki in sending Ex-Aid to the World of Kyuranger is evident in that Kyuranger's setting uniquely sees Earth under the occupation of the Space Shogunate Jark MatterIcon-crosswiki which is not present in Ex-Aid. Space.7: Take Back the Birthday! Lucky's later visit to the World of Kamen Rider Ex-Aid was presumably achieved through similar means. Go Together, Embracing Your Ambitions!

Similarily, the World of Ex-Aid (エグゼイドの世界 Eguzeido no Sekai) is used for the crossover Kamen Rider Heisei Generations FINAL: Build & Ex-Aid with Legend Riders (2017) to distinguish the prime reality home to Ex-Aid and other starring Riders such as Ghost, Gaim, Fourze and OOO, from the seperate World of Build.

A.R. World

In material for All Riders vs. Dai-Shocker, the World of Kamen Rider (仮面ライダーの世界 Kamen Raidā no Sekai) refers to the A.R. World where Shocker executive Ambassador Hell of Dai-Shocker originally came from.


As the prime universe, this reality features throughout the vast majority of the TV series and films, those relevant are listed here.

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