A cool plot might be a sort of exchange program. A few Hogwarts students go to the Hidden Leaf Village and vice versa. The Hogwarts students learn about chakra and how to use it, while the ninja learn about different types of magic. Harry could befriend Naruto and they could combine their powers to fight off a group of Death Eaters and rogue ninjas who are teaming up to cause chaos in both worlds.
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.
Perhaps there is a prophecy in both the wizarding world and the ninja world that foretells of a hero who combines the powers of both. Naruto and Harry are both seen as potential candidates. They start off as rivals, trying to prove they are the one from the prophecy. But as they get to know each other and face challenges together, they realize that they need to work together to fulfill the prophecy and save both their worlds from a great evil.
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.
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 idea could be that the X - Men visit Hogwarts to teach the students about mutant powers and how to co - exist with those who are different. Another could be that Harry Potter discovers he has mutant abilities and has to navigate both the wizarding world and the world of mutants.
One idea could be that Tonks gets involved in Harry's search for Horcruxes. Maybe her Metamorphmagus abilities help them in disguising and sneaking into places undetected. For example, she could transform into a Death Eater to infiltrate their meetings and gather information.
One idea could be that the Death Eaters in the Harry Potter world somehow gain access to Hollow powers from Bleach. This could create a new kind of dark magic that the Order of the Phoenix has to deal with. Another plot could involve Hogwarts students being sent to the Soul Society for a special training exchange, and they have to adapt to the different spiritual powers and rules there. And perhaps a powerful Hollows attacks Hogwarts and the wizards have to team up with the Soul Reapers to defeat it.
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.
One idea could be introducing a new character from another universe who accidentally gets transported into the Goblet of Fire timeline. This character could have unique magical abilities that both fascinate and worry the Hogwarts students. For example, they might be able to control time in a different way than Hermione's time - turner. Another plot idea could be that Voldemort discovers a new dark magic spell from this other universe through a mysterious object. This could make him even more powerful and the trio has to find a way to stop him using knowledge from both universes. Also, what if the Goblet of Fire chooses a student from a completely different magical school in this crossover? It would create a whole new dynamic of competition and friendship.
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.
Well, perhaps there could be a situation where the Ministry of Magic tries to regulate mutant powers as they do with magic. Some mutants might resist this and seek refuge at Xavier's School for Gifted Youngsters. In the crossover, Professor McGonagall and Professor X could have an interesting exchange of teaching methods. McGonagall's strict yet nurturing style compared to Professor X's more accepting and guiding style. Also, imagine a character like Rogue being at Hogwarts. She could accidentally absorb the powers of a wizard, creating all sorts of chaos and a new mystery to solve.