|This article is about a/an companion/transformation device/ally in Kamen Rider Decade.|
|Season:||Kamen Rider Decade|
|Homeworld:||Earth (AR Kiva World)|
|First Appearance:||Second Movement ♬ Prince Kiva|
|Last Appearance:||Kamen Rider × Kamen Rider W & Decade: Movie War 2010|
|Number of Episode|
She is extremely tiny, small enough to be hidden in an adult's closed fist. She learns of Decade from Narutaki, and uses her power to bring Yusuke into her world, and then sends Tsukasa into another to do battle with Kaixa. She later ends up traveling with the Hikari Studio, though remaining in contact with Narutaki with only Natsumi aware of it. She seems to like Yusuke the most out of the traveling group as she is delighted when he returns to travel with them after they leave the World of Agito. In the World of Hibiki, she assists Ouja in summoning a Bakegani to be used on Decade as Gyuki was not getting the job done, placing her overall goals further into question.
In Kamen Rider × Kamen Rider W & Decade: Movie War 2010, Kiva-la is revealed to be the means for Natsumi to assume her Kamen Rider form: Kamen Rider Kiva-la.