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.
It's hard to say. Naruto has his huge chakra reserves and powerful jutsu. But Harry has the power of love and some really strong spells. However, I think Dumbledore would be very powerful in this crossover. He has great wisdom and extremely powerful magic. He could probably figure out how to use Naruto's chakra to his advantage if they were on the same side.
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.
One common theme is the clash of different cultures. For example, when Harry Potter crosses with Star Trek, the scientific and technological culture of Star Trek clashes with the magical culture of Harry Potter. Another theme is the exploration of new powers. When combined with something like the X - Men, new powers and abilities can be explored. Also, friendship often remains a key theme. No matter what world Harry enters in the crossover, his ability to form strong friendships and alliances is always important.
Maybe Voldemort's return somehow affects the Magical Dimension where the Winx Club exists. The Winx girls then team up with Harry Potter and his friends to fight against the dark forces. Stella could use her light - based magic to counter some of the dark spells, while Hermione and Flora could exchange knowledge about magical plants.
Harry and Naruto would be an obvious and very interesting pairing. They are both the main heroes in their respective stories, so seeing them interact, share their experiences, and learn from each other would be great. Hermione and Sakura could also be a fascinating pair. Both are intelligent and strong - willed female characters. Hermione could teach Sakura about complex magic theories, while Sakura could show Hermione some of her medical ninjutsu skills.
One great fem Harry Potter crossover Naruto fanfiction is 'The Potter-Namikaze'. It combines the magic of the Harry Potter world with the ninja skills of Naruto. The story follows a female Harry Potter who somehow ends up in the Naruto universe and has to adapt. It's full of interesting character interactions and unique plot twists.
One possible plot could be that the Death Eaters in the Harry Potter world team up with the Akatsuki from Naruto. Harry and his friends, along with Naruto and his comrades, have to join forces to stop this powerful alliance. They could learn from each other's magic and jutsu. For example, Naruto could teach the wizards about chakra control, and the wizards could show Naruto some advanced spells for defense and offense.
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.
The unique feature is the combination of different magical universes. Neville from 'Harry Potter' gets to interact with elements from other fictional worlds. This can lead to really interesting plot twists. Say, if it's a crossover with a time - traveling story, Neville might have to deal with time paradoxes using his Hogwarts - taught magic. It also allows for new character relationships to form, like Neville befriending a character from a different magical realm who has completely different values and powers.