The plot changes would be interesting. Naruto's presence might make the Noblesse characters question their own values. His journey to be recognized and respected in his own world could translate into a similar arc in the Noblesse world. He could also introduce new forms of combat and training. For example, his ability to learn new jutsus quickly could inspire some of the Noblesse characters to seek new ways of increasing their power. And his sense of loyalty and friendship would surely shake up the relationships in the Noblesse fanfic.
Naruto's abilities would be quite a novelty in the Noblesse universe. His chakra, for instance, is a different form of energy compared to what's in Noblesse. His shadow clone jutsu could be used for various purposes like scouting or overwhelming opponents in battles. His Rasengan could be a powerful attack against Noblesse enemies. And his ability to tap into the Nine - Tails' chakra would make him extremely powerful, perhaps even on a level that would rival some of the strongest Noblesse characters.
To write an engaging plot for a Naruto Noblesse crossover fanfiction, first, study the unique elements of both universes. For Naruto, there are ninjas, chakra, and the complex shinobi world. In Noblesse, there are powerful vampires and their hierarchical society. Combine these elements in an interesting way. For example, what if a Naruto character stumbles upon the Noblesse world? Maybe Naruto himself gets transported there. He could use his ninja skills in unexpected ways in the vampire - dominated world. This would create a lot of interesting scenarios and conflicts.
One common theme is the exploration of their relationship. Since they are both important characters in Noblesse, fanfics often delve into how they interact with each other, their feelings towards one another, whether it's a platonic bond or something more romantic.
One interesting pairing could be Naruto and Rai. Naruto's energetic and determined nature could contrast with Rai's calm and powerful vampire leadership. They could learn from each other, with Naruto teaching Rai about the value of friendship and hard work in the shinobi way, and Rai showing Naruto how to control and enhance his power in a different way. Another pairing could be Sakura and Seira. Sakura's medical skills could be useful in the Noblesse world, and she could bond with Seira over their shared sense of loyalty and protection of their friends.
Hard to say. It depends on various factors like the popularity, the creative team's plans, and market demand. But you can follow related news channels for the latest updates.
You can try fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfics on various topics, including Noblesse. Just search for 'Noblesse Rai x Raskreia' and you'll likely find some interesting reads.
Perhaps a fanfic could explore a scenario where Rai has to pretend to be a normal human for some reason, and Frankenstein has to help him blend in. This would be full of comical moments as Rai tries to understand human customs and behaviors, all while Frankenstein is there to keep him out of trouble and protect his true identity.
In my opinion, it's hard to say which is better. The Noblesse manhwa has a unique charm in its original illustrations and story presentation. On the other hand, the anime adds a dynamic element with its animations and sometimes expands on certain aspects. It really comes down to personal taste.