SPEAKING OF GAIM! I forgot to add something: Despite Gaim being a godlike entity, his belt and lockseeds were also sealed, however he's still alive and well.

More important stuff: To become Kamen Rider Kiva you still need to have fangire blood, just like the original, if you get an explanation and for Decade and neo heisei riders, you may make your own belts up, but that will need explanation, and you necessarily will need to use the power items (rider cards, gaia memmories, OOO medals) on them.