A.R. Worlds

File:The universes in HGF.jpg
Within the franchise, Kamen Riders exist within the multiverse in several different **Alternate Reality Worlds**, or simply **A.R. Worlds** (A（エイ）.R（アー）.WORLD（ワールド）, *Ei.Ā. Wārudo*) though referred as "World" (世界, *Sekai*) individually.

## Concept

The concept of the Multiverse refers to the existence of countless parallel universes that comprise of all that exists. According to Tsukasa Kadoya, the overseer of these worlds, he claims that every single Rider exists on their own separate plane, with Sougo Tokiwa himself being the only one capable of either uniting them or keeping them separate.

The worlds are usually are inline in both date and time 「*Kamen Rider Decade*」, though there will be differences here and there in terms of the time flow. 「*Kamen Rider Heisei Generations FINAL: Build & Ex-Aid with Legend Riders*」.

Decade Worlds.pngThe A.R. Worlds in *Kamen Rider Decade*Build Worlds.pngThe parallel worlds in *Kamen Rider Build*20 Heisei Rider Worlds.pngThe 20 Heisei Rider Worlds in *Kamen Rider Zi-O*
## List of Known Worlds

### Original Worlds

The following are the individual worlds in which each *Kamen Rider* series take place in. During the *Kamen Rider* franchise's revival in the 2000s, each season were originally standalone and self-contained. However, from the start of the Heisei Era's second phase, these previously unrelated works were put together into a single, shared continuity, with *Kamen Rider Zi-O* ending with the twenty Heisei Riders all back in their own universes.

### *Kamen Rider Decade* A.R. Worlds

The characters of Kamen Rider Decade exist amongst various different iterations of reality that are based on the previous entries of the Kamen Rider Series that have aired during the Heisei period of Japanese history. Each differs in some way from the series on which it was based.

### Reboot Worlds

The following are the individual worlds where were remade from the original Kamen Rider Series.

 *Kamen Rider Black Sun* Universe
 *Shin Kamen Rider* Universe

### Other Worlds

The following are other worlds in the multiverse beyond Kamen Rider Decade.

### Merged Worlds

The following are worlds in the multiverse that have merged into one unified Earth, some have split back into different worlds after the crisis was averted.

 *Zi-O VS Decade* Universe

## Subdimensions

In the metaseries, there exists worlds that exist on a different dimensional plane, and interact within the continuity of the real world.

 Wonder World (ワンダーワールド, *Wandā Wārudo*) | This world is a colorful fantasy world, populated not only by humans, but also by different creatures, mechanical God Beasts, Animals and Story Characters.

## List of Known Timelines

### Alternate Timelines

The following are alternate timelines within the *Kamen Rider* franchise. The presence of divergent timelines exist within each universe, producing various alternative futures, potential outcomes, and alternate histories.

### Altered Timelines

The following are altered timelines within the *Kamen Rider* franchise. In contrast to the alternate timelines, these periods were revised through means of time travel, creating a vastly separate timeline, and would often be restored back to normal according to history.

## Behind the scenes

The concept of A.R. Worlds was first introduced in *Kamen Rider Decade*, which brought the first ten Heisei Riders together for the first time. Whilst the Showa Riders were thought to share a single world, with crossovers between them being fairly common, the Heisei series was much less interconnected.

Starting with *Kamen Rider W*, several trends were introduced in an effort to bridge multiple seasons together into a single world, including easter eggs, pre-series cameos in movies, as well as the Movie War crossover series. The Kamen Rider series would also begin to crossover with the Super Sentai series. *Kamen Rider Build* would later be the first Rider season to explicitly distinguish itself as occurring in a separate world from the rest of the Rider seasons.

The final Heisei season, *Kamen Rider Zi-O*, would later establish each of the Heisei Rider seasons as taking place in their own worlds. While this would also be the standard for the Reiwa era going forward, crossovers amongst different seasons would still take place, making the Rider multiverse, and by extension the Toei multiverse, similar to the floating timeline concept in comics — or more aptly, a "floating multiverse", whereby each season mostly takes place in their own world, but they may intersect with one another at several points wherever necessary.

It is to be noted that Toei themselves has not explicitly defined a strict continuity with each of their tokusatsu series.

## Notes

* The multiverse theory is a famous concept explored most often in science-fiction stories, particularly in DC Comics mythology, as well as Marvel Comics, where alternate scenarios are depicted in timelines where historical events played out differently like certain people in history were never born, killed before a major event, or even were born a different gender. It can even depict technologies advancing further or hindering depending on certain historical factors and/or changes to the political spectrum.
	+ In terms of real science, it is explained that as an individual makes a decision, there exists another (parallel) universe in which they did not make that decision. While the concept has been debated consistently, several scientists are divided as to whenever the parallel universe theory exists, thus has removed its legitimacy as an actual scientific inquiry.

## See also

* Nine Worlds
* New Worlds

## References

1. ↑ https://news.mynavi.jp/article/20210905-1964727/4