In a Naruto - Harry Potter crossover with an immortal Naruto, he could be a sort of mysterious figure in the wizarding world. His immortality might make him a target for some dark wizards who want to study or steal his power. Naruto, being Naruto, would likely try to make friends and allies first. He could use his Rasengan, which might be seen as a very unique and powerful form of magic in the Harry Potter world, to protect those he cares about. He might also be interested in the concept of the Philosopher's Stone, as it has to do with immortality. Maybe he could offer his own knowledge of immortality to help protect the stone or find a better way to use its power without causing chaos.
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.
Maybe in this fanfiction, the Death Eaters are somehow connected to an evil ninja clan in the Naruto universe. Harry and Naruto then have to team up to fight against this combined threat. Naruto could teach Harry how to use chakra to enhance his physical abilities, and Harry could show Naruto some of the more subtle uses of magic, like invisibility spells that could be useful for stealth missions.
Maybe some of the Hogwarts students are sent to the Naruto universe. They would be amazed by the ninja techniques. Hermione, for instance, would be eager to study how chakra works and might even find a way to combine it with magic. Harry could learn some ninja stealth skills which would be useful in his fight against Voldemort.
One creative idea is time - travel fanfictions. For example, a character might go back in time to prevent certain tragedies from happening in the 'Harry Potter' story. Another idea is crossovers, like 'Harry Potter' and 'Lord of the Rings' crossovers, where characters from both universes interact.
Well, in 'harry potter immortal crossover fanfiction', there might be a plot where an immortal being tries to change the course of the wizarding war. Since they are immortal, they might have knowledge and resources that could tip the balance. They could also introduce new forms of magic that are more powerful or dangerous. It could also explore how the immortal's view on life and death affects the characters in the Harry Potter world, like making them question the value of their own mortality.
One idea could be that the Hogwarts students are visited by Naruto and his friends. Naruto could show off his ninja skills, like the Shadow Clone Jutsu, which would amaze the wizards. The wizards, in turn, could introduce Naruto to magic like the Patronus Charm. Another plot could involve a common enemy that requires both the power of ninjutsu and magic to defeat. For example, a dark wizard who has also acquired some dark ninja arts.
One idea could be that Naruto is somehow transported to the wizarding world. He might attend Hogwarts and use his ninja skills in the wizarding duels. His chakra could be seen as a unique form of magic there.
Well, for a Harry Potter and Naruto crossover fanfic, a cool plot could be that there is a dark force emerging that is a combination of Voldemort's magic and the Akatsuki's evil intentions. Harry Potter and Naruto then join forces. They start by training together, with Naruto teaching Harry some basic ninja moves like tree - walking to improve his physical abilities, and Harry teaching Naruto some basic spells for protection. Along the way, they gather their friends from both worlds, Hermione and Sasuke for example, to fight against this new threat.
In an 'immortal naruto x harry potter fanfiction', Naruto's immortality might be a result of some powerful sealing jutsu gone wrong or right. He arrives in the wizarding world and is initially confused by the different rules of magic. But he quickly adapts. He could form an alliance with Harry Potter. Together, they could explore the similarities and differences between ninjutsu and magic. For example, Naruto's shadow clone jutsu could be compared to the wizard's duplication spells. They could then use their combined skills to protect both the ninja world and the wizarding world from threats that are starting to cross over between the two realms.
One interesting plot idea could be Naruto's chakra system interacting with magic in the Harry Potter world. For example, his ability to use shadow clones might be seen as a form of magic by the wizards. Another idea could be Naruto being sorted into a Hogwarts house, perhaps Gryffindor because of his courage. Or maybe he could teach the Hogwarts students some of his ninja skills in a special class.
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.