In fanfiction, Naruto characters would have to adapt to the different power systems. In the Rosario + Vampire world, there is magic and different vampire abilities. A character like Rock Lee would have to learn to use his taijutsu in a world where there are flying creatures and magic spells. Meanwhile, the Rosario + Vampire characters might be intrigued by the Naruto characters' use of chakra. They could try to learn it, which would create a whole new set of stories and interactions.
Well, think about it this way. In the Rosario + Vampire universe, there are many different species and hierarchies. Naruto characters could disrupt or integrate into these. For example, Kakashi could use his intelligence and combat experience to navigate the complex politics of the Rosario + Vampire world. He might end up being a mediator between different groups. And the Naruto characters' values of loyalty and friendship could have a big impact on the relationships in the Rosario + Vampire world.
Well, he could fit in as a unique addition to the cast. His ninja abilities would be quite different from the normal powers in the Rosario Vampire world. He might be seen as a wildcard, with his speed and combat skills being a big advantage.
Shirou's projection magic could be really interesting in the Rosario Vampire world. He could project weapons that are effective against the various supernatural beings there. For example, if there are werewolves, he could project a silver - edged sword.
The characters would have very interesting interactions. Naruto would probably be curious about the vampires and their powers. The vampires, on the other hand, might be wary of Naruto at first. And if there's a dragon character, it could be a source of awe for everyone. For instance, Naruto might try to befriend some of the Rosario Vampire characters, while they might be hesitant because of his different nature.
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.
Vampire Anna could be an outcast in the Frozen fanfiction universe. Since she's a vampire, she might be feared by the people of Arendelle who don't understand her new nature. But she could also use her abilities to help protect the kingdom in secret. For instance, she could use her enhanced senses to detect approaching threats.
Naruto could be seen as a unique kind of 'monster' in the Monster High world. His ability to use chakra and perform ninjutsu would be very different from what the Monster High students are used to. He might befriend some of the more outcast characters, like Frankie Stein, because he also knows what it's like to be different. His positive attitude would also bring a new energy to the Monster High school.
Sasuke could be seen as a kind of dark and brooding figure that the Addams Family might respect. His quest for power and revenge could be something they find interesting. Naruto, on the other hand, with his bright and positive attitude, would be a contrast to the Addams Family's usual aesthetic but could bring a new kind of energy to their world.
Tsukune could fit in as an outsider with unique abilities. His vampire powers would be a contrast to the ice - based powers in the Sub Zero world. He might be initially seen as a threat or a curiosity.
Well, Goku's extreme power level could make him a sort of legend in the Naruto fanfiction world. His Saiyan abilities like the Kamehameha and Super Saiyan forms would be completely foreign to the ninjas. He might be seen as an otherworldly being, and his presence could disrupt the power balance. Maybe he'd come to the Naruto world seeking a new challenge, or perhaps he was accidentally transported there.
Well, Gojo could be a super powerful outsider. Maybe he comes to the Naruto world to study its unique chakra system. His Infinity ability would be a game - changer. He could use it to easily deflect most ninjutsu attacks. And his Six Eyes could help him detect hidden enemies or traps that normal shinobi might miss.