|This article is about a/an alternate reality/A.R. World (another rider's world) in Kamen Rider Decade.|
The World of Kiva (キバの世界 Kiba no Sekai?) is the alternate reality where a version of Kamen Rider Kiva takes place. Unlike the original series, this world allows Fangires and humans to coexist, with the King's servants destroying the rebellious Fangires. The backdrop that allows entry into the World of Kiva depicts a nighttime cityscape with Castle Doran emerging from a building. Within this A.R. World, Tsukasa assumes the identity of a violinist with the talent of playing violin solo similar to those of Otoya and Wataru Kurenai.
- Kivat-bat the 3rd
- Arms Monsters
- Ryo Itoya
- Beetle Fangire
- The Fangires
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 Kiva is, as one of the Nine Worlds, not an alternate reality like in the TV series but the original world. The World of Kiva is one of the six worlds the Hikari Studio group, Tsukasa/Decade, Kaito/Diend, and Natsumi, have already traveled to by the start of the novel as they head for the three remaining worlds, and thus not much is seen about it.