One idea could be that Naruto, with the power of the Kyuubi, somehow ends up in the Rosario Vampire world. He could use his ninja skills and the Kyuubi's chakra to face the various supernatural threats in that world. Maybe he teams up with Tsukune and the other characters to protect the school from an even greater evil.
One interesting fanfiction could be where Naruto, with his Kyuubi powers, somehow gets involved in the world of Rosario Vampire. Maybe he's on a mission and stumbles upon the school. It could be a story full of action and unique character interactions.
Naruto could be a new student at the Yokai Academy. His presence with the Kyuubi's power would disrupt the balance. For example, the vampires might see him as a threat or a potential ally. He could use his shadow clones to spy on different factions, like the witches or werewolves, to understand the politics of the school better.
In a Naruto, Kyuubi and Rosario Vampire fanfiction, there could be a plot where a character from Rosario Vampire travels to the Naruto world and discovers the legend of the Kyuubi. This character could then try to bring the power of the Kyuubi back to their own world, creating a whole new set of adventures and challenges as they deal with the different cultures and powers in both worlds.
His relationship with the Kyuubi could also change in the context of the Rosario Vampire fanfiction. Maybe the Kyuubi senses the unique supernatural elements in this new world and warns Naruto about certain hidden dangers. This could lead to a deeper bond between Naruto and the Kyuubi as they navigate this strange new place together. And Naruto could gain new abilities or ways of using his chakra influenced by the Kyuubi in this different setting.
I'm not sure if there is such a specific fanfiction where a character from Rosario Vampire is reading Naruto fanfiction. Fanfiction can be very diverse, but this seems like a rather unique and specific concept. It's possible that it might exist in the vast realm of fan - created stories, but it would be quite difficult to find without a more targeted search.
The plot might involve a threat that endangers both Naruto's world and the world of Rosario Vampire. Naruto, with his Kyuubi - enhanced abilities, teams up with the vampires and other creatures in Rosario Vampire. They'd have to combine their different powers, like Naruto's Rasengan and the vampires' super strength, to fight against the common enemy. It would be a wild mix of ninja action and vampire drama.
Naruto would probably be very curious about the vampires and other creatures in Rosario Vampire. He'd be his usual friendly self, trying to make friends. The vampires might be initially wary of him, especially with the Kyuubi's power, but his positive attitude could win them over. Tsukune, from Rosario Vampire, could learn a lot from Naruto about determination and fighting spirit.
In some fanfictions, the blend starts with Naruto being transported to the Rosario Vampire world. His Kyuubi powers are something completely new there. The power dynamics in the Rosario Vampire world are mainly based on vampire and monster abilities, and Naruto's chakra and Kyuubi - enhanced skills disrupt that in an interesting way.
One idea could be a crossover where Naruto characters end up in the Rosario + Vampire world. For example, Naruto could be mistaken for a powerful yokai due to his chakra. Sakura might study the unique magic in the Rosario + Vampire world. Another could be a vampire in the Naruto world, using their powers in a different way than the normal jutsu.