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.
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 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.
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 great Harry Potter X - Men crossover slash fanfiction is 'Magical Mutants'. It combines the magical world of Harry Potter with the mutant powers of X - Men in a really unique way. The characters from both universes interact in a believable manner, and the slash aspect adds an interesting layer of relationship exploration between certain characters.
Perhaps there could be a plot where a powerful dark wizard in the Harry Potter universe creates a spell that merges the two worlds. This causes chaos as ninjas and wizards start to clash due to misunderstandings. Naruto and Harry, realizing the danger, form a group of their friends from both worlds. They include Hermione, Ron, Sasuke, and Sakura. Together, they try to find a way to reverse the spell while also learning from each other. Naruto teaches the wizards about chakra control, and the wizards teach the ninjas about potions and magical creatures.
One interesting female Harry Potter Naruto crossover fanfiction could be 'The Magic of Shinobi'. In this story, the female Harry Potter character finds herself in the Naruto universe and has to adapt to the ninja way. She uses her magic skills in unique ways within the context of the Naruto world, like using spells to enhance her ninja training or to outwit opponents in battles.
To write an engaging Harry Potter and Naruto: Kurama fanfiction crossover, first understand the unique elements of each universe. For Harry Potter, it's the magic system like spells and potions. In Naruto, Kurama is a powerful and complex character. Combine these elements in an interesting way. For example, you could have Kurama's chakra interact with Harry's magic in a battle against a common enemy. Start with a strong premise that would draw in fans of both series.
The most interesting aspect is the combination of magic systems. The unique jutsu in Naruto and the spells in Harry Potter can create really exciting scenarios. For instance, a wizard using a Patronus charm against a Naruto - style demon. Another aspect is the character interactions. Imagining Naruto and Harry as friends or rivals is very appealing.
Voldemort could still be the main villain in a different way. Suppose he discovers Tonks' unique connection to Harry and tries to use her as a weapon against him. He could manipulate her mind or put her in dangerous situations to force Harry to make sacrifices or bad decisions.