Red, blue, green, and purple so far. But I'm quite sure there are more coming in the future.
For your information, such ability isn't new anymore. Kamen Rider Kuuga, which happens to be the last Kamen Rider series I paid attention to was the first to feature such color variation. It looks like Kiva is reliving this idea again. As a matter of fact, there are so many similarities between the two, Kiva looks almost like Kuuga reincarnated to me now ^^; Apart from the similarity of the colors, even the appearance or absence of shoulder armors in certain forms look coincidental (or maybe not?) with Kuuga. The similarity sure is a good thing to me, since I really enjoyed Kuuga some seven years ago. But I do hope Kiva won't be following its predecessor completely.
On the right is Kamen Rider Hunter, the second Kamen Rider in the series. Will he be an ally of Kiva, or his enemy instead?
Apart from the color variation, another major similarity between Kiva and Kuuga is the ability of his motorbike to combine with another mecha to form a bigger and cooler one. For Kuuga, the add-on mecha is an ancient beetle, for Kiva, it's... ... a statue? ^^;
Titan Kuuga (purple) uses a sword, while Pegasus Kuuga (green) uses a crossbow; the weapon for Purple Kiva is a dagger (?), and a pistol for Green Kiva. Similarity again?
Another Castle Dran in red? Don't tell me Castle Dran shares Kiva's ability to shift color as well XD
All images from Toysdaily.
