Well, it could be about a character from Kamen Rider Kiva getting transported to the Naruto universe. Maybe the Kiva character has to learn chakra control and ninjutsu while also trying to find a way back to his own world. He could team up with Naruto and his friends to fight common enemies like the Akatsuki who might be interested in the Kiva powers.
Masked Knight Kiva's list was as follows: Kamen Rider Kiva Kamen Rider Kiva 2017 Kamen Rider Kiva -Dragon Me Kamen Rider Kiva -Dragon I 2 Kamen Rider Kiva -Dragon Me 2017 6. Kamen Rider Kiva Kamen Rider Kiva (2) 8 Kamen Rider Kiva Superstar 2017 9 Kamen Rider Kiva Super Actor-Dragon Me Kamen Rider Kiva Super Actor-Dragon Me 2 11 Kamen Rider Kiva Superstar-Dragon Me 2017 Kamen Rider Kiva's Super Strength Kamen Rider Kiva's Super Strength (2) Kamen Rider Kiva Super Power 2017 Kamen Rider Kiva's Super Strength-Dragon Me Kamen Rider Kiva's Super Strength-Dragon Me 2 Kamen Rider Kiva's Super Power-Dragon Me 2017 Masked Rider Kiva's Super Acting Ability Masked Rider Kiva's Super Acting Ability (2) Masked Rider Kiva's Super Acting Ability 2017 Kamen Rider Kiva's Super Acting Ability-Dragon Me Masked Rider Kiva's Super Acting Ability-Dragon Me 2 Kamen Rider Kiva's Super Acting Ability-Dragon Me 2017 Masked Rider Kiva's Superperformance Plan Masked Rider Kiva's Super-Performance Plan (2) Kamen Rider Kiva Super-Performance Plan 2017 Kamen Rider Kiva Super Actor-Dragon Me Kamen Rider Kiva Super Actor-Dragon Me 2 29 Kamen Rider Kiva Super Actor-Dragon Me 2017 Masked Rider Kiva's Superperformance: The Source of Power
One idea could be a crossover with another Kamen Rider series, like Kamen Rider Decade. The two riders could team up to fight a common enemy that has the power to travel between different Kiva - related worlds. This would bring a mix of their unique fighting styles and powers.
In terms of anime characters, Ichigo Kurosaki from 'Bleach' could be an interesting addition. His ability to see and fight spirits could be related to Kiva's battles with Fangires. They could end up in each other's worlds and have to learn to use their powers together to fight off both Hollows and Fangires.
One possible plot could be that Naruto somehow gets transported to the Kamen Rider universe. He might initially be seen as a threat due to his powerful ninja skills. The Kamen Riders could try to stop him, thinking he's a new kind of monster. But as the story progresses, they realize he's not evil and they team up to fight a common enemy that threatens both their worlds.
The Kiva characters could be seen as strange visitors at first. For instance, Kiva himself could be mistaken for a new type of ninja with his unique powers. He might have to prove himself to the ninja villages. His ability to transform could be seen as a very advanced form of jutsu that no one has ever seen before.
A plot could involve a Kamen Rider who has the ability to use chakra like in the Naruto world. He meets Naruto and they exchange their skills. The Kamen Rider teaches Naruto about his technology and fighting style, while Naruto teaches the Kamen Rider about ninjutsu. Then they have to face a powerful villain who is after the unique combination of their powers.
Well, a really interesting crossover concept could be a time - travel plot. Kiva travels to the Naruto universe and gets involved in the shinobi wars. Or Naruto somehow ends up in Kiva's world and has to deal with the politics and power struggles there among the Fangire clans while also trying to find a way back home. It could also be about a shared enemy that has the ability to disrupt both the balance of chakra in Naruto's world and the peace between humans and Fangires in Kiva's world.
One interesting Kiva fanfiction could be about a new rider who teams up with Kiva to fight an ancient evil that has resurfaced. They might have to combine their powers in unique ways to defeat the powerful foe.
First, you need to study both universes well. Know the characters, their powers, and the rules of their worlds. For Naruto, understand the chakra system, and for Kiva, know about the Fangires and the Kivat - based powers. Then, come up with a unique plot. Maybe something that combines the ninja - like stealth and combat with Kiva's more supernatural battles.
One possible plot could be that in a world where Naruto and Kamen Rider exist together, Naruto, for some reason, sees the Kamen Rider as a threat to his village's safety. Maybe the Kamen Rider's powers are misconstrued as dark magic. So Naruto, in his role as Hokage or a high - ranking shinobi, banishes the Kamen Rider. This could lead to the Kamen Rider having to prove his innocence and find a way back to the village to clear his name.