One idea could be that Naruto's immortality is due to some sort of ancient ninja magic that has parallels to the magic in the Harry Potter universe. For example, he could have made a pact with a powerful magical creature in the Naruto world that gives him eternal life, and when he enters the Harry Potter world, he has to figure out how this magic works there. Maybe he tries to find a way to share his immortality with his new friends in Hogwarts, like Harry, Hermione, and Ron. He could also use his ninja skills along with his immortality to protect the wizarding world from new threats that the regular wizards are not equipped to handle.
Well, in a Harry Potter fanfic, an immortal Naruto could be a mentor figure. He'd bring his own set of values from the Naruto world. His immortality would make him a source of great knowledge, having lived through so many experiences. He could teach the Hogwarts students new ways of combat and self - defense that are different from magic.
Well, if Naruto was immortal in a Harry Potter fanfiction, it could be really interesting. He could use his ninja skills to deal with the magical threats in the wizarding world. For example, his shadow clone jutsu could be used for various tasks like scouting or distracting dark wizards. His chakra control might also help him in learning magic faster as it's a form of energy control similar to magic in some ways.
One common theme is the clash of cultures. Naruto comes from a world of ninjas and Harry Potter from a world of wizards. So, when they are combined, there is often a struggle to understand each other's ways. For example, Naruto might not understand the concept of magic wands at first, and the Hogwarts students might be baffled by his chakra use.
In the fanfiction, Naruto's immortality could make him a key figure in resolving long - standing conflicts. He has the time and the power to study both the wizarding and ninja worlds deeply. So he could use his knowledge to find solutions to problems that have been plaguing the wizarding world for ages, like the fight between pure - bloods and half - bloods or the threat of dark wizards. His presence would bring a new dynamic to the story as he doesn't have the same limitations as the regular Harry Potter characters in terms of lifespan and the type of power he wields.
In the Harry Potter fanfiction world, an immortal Naruto would be a force to be reckoned with. He could use his Sage Mode to sense magical energies in a different way. He might even try to find a way to transfer his immortality to his friends in the wizarding world if they were in danger. His ability to never die would make him a valuable ally in the fight against the dark forces. He could keep coming back no matter how many times he was defeated, which would be a great advantage.
One popular 'naruto immortal harry potter fanfiction' is 'Naruto in Hogwarts'. It's really interesting as it combines the magical world of Harry Potter with Naruto's ninja skills. The story often has Naruto arriving at Hogwarts and causing quite a stir with his unique abilities.
He could be a new teacher at Hogwarts. Since he's immortal, he has a vast amount of knowledge and skills. He could teach a new subject that combines ninja techniques and magic. For example, he could teach students how to use their magic in a more physical and combat - oriented way, like ninjas do.
In some fanfictions, Harry might use his magic skills. For example, he could use spells to protect Naruto from a powerful enemy. Maybe he casts a shield charm to block an attack that Naruto couldn't avoid on his own.
Well, one way the storyline could develop is that Naruto's immortality would give him an edge in the wizarding world. He could use his ninja skills along with newfound magic abilities. Maybe he'd be a bit of an outlier in Hogwarts, not fully understanding the magic system at first but quickly adapting due to his ninja training. His immortality might make some dark wizards target him, thinking he holds some sort of secret to eternal life. And he'd probably form unique friendships, like with Harry, Ron and Hermione, teaching them some ninja moves in return for magic lessons.