If Naruto was Harry's father in the fanfiction, the story's power dynamics would shift. Naruto is used to dealing with threats on a large scale in his own world. He would bring that experience to the fight against Voldemort. Instead of relying solely on the Order of the Phoenix, Naruto might form his own group of allies, including some ninja - like characters he brings from his world. Also, Harry's understanding of loyalty and friendship would be deeper. Naruto values his friends above all else, and he would instill that in Harry from a young age, which could lead to different decisions in the story.
Harry's character would be more conflicted. On one hand, he has his natural inclination towards good from his original Potter bloodline. But on the other hand, Zeref's upbringing would expose him to darker elements. So he would constantly be at war within himself about what is right and wrong. For example, he might be tempted to use more aggressive or unethical magic to achieve his goals, yet still have that inner voice telling him it's wrong. Also, he would be more secretive, not sharing his thoughts and plans easily with others, as Zeref is often a rather mysterious character himself.
If Harry isn't the Boy Who Lived, it might mean a shift in the power dynamics within the wizarding world. Different characters could rise to prominence and the plot could take unexpected turns. Also, Harry's relationships with others might change as his status is different.
Harry might become more bold and aggressive in his approach. Since Grimmjow is known for his brash and fearless nature, Harry could start to take more risks without thinking too much about the consequences. He may also become more interested in physical combat rather than just relying on magic. For example, he might start training his body more like Grimmjow trains his combat skills.
His sense of justice could be more absolute. The Norse gods have a clear - cut view of right and wrong. Harry, influenced by them, would not tolerate any form of injustice. He would be more likely to take immediate action against wrongdoers, rather than waiting for the proper procedures in the wizarding world like waiting for a trial. He might be more of a vigilante, but with a strong moral compass guided by the Norse gods' values.
One big change would be his magical education. In Ancient Egypt, it might focus more on spells related to the sun, the Nile, and the afterlife. His family structure could also be different. Instead of the Dursleys, he could be part of an Egyptian wizarding family. His enemies might not be Death Eaters but some sort of ancient Egyptian dark forces. He could have a different Patronus, perhaps something related to an Egyptian animal like a cat or a falcon.
Ron and Hermione become even more protective of Harry. They are constantly by his side, trying to cheer him up. Their relationship with Harry deepens as they share his pain. In some fanfictions, this brings Ron and Hermione closer together romantically as well, as they bond over their shared concern for Harry.
His sense of adventure might be different. In Narnia, he would be dealing with things like talking beavers and magical forests from a young age. So his idea of adventure would be more Narnian - themed. He might be more in touch with nature compared to his Hogwarts self.
It would be quite a wild concept. Naruto's energetic and determined personality would likely have a big impact on Harry. He might teach Harry some physical combat skills alongside magic. And the story could have Naruto introducing some of his own world's concepts, like the ninja way, to the wizarding world.
He would probably be more power - hungry. Thanos was constantly seeking power through the Infinity Stones. Naruto, who has always been about protecting his village and friends, could shift his focus more towards personal power gain. This might lead him to isolate himself from his friends as he pursues greater power, just like how Thanos was mostly alone in his quest.
Well, when this happens, there could be a major upheaval in the magical world. Harry's powers might develop in unexpected ways, and his role in the fight against evil could take a wild turn. Also, his friendships and alliances could be redefined.