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.
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.
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.
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.
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.
His magical abilities might be influenced by the Norse magic system. He could have a more primal and elemental approach to magic, perhaps being able to control natural forces like thunder (associated with Thor) or ice (linked to some Norse entities).
In such a fanfiction, perhaps Harry would grow up with god - like powers. He might learn magic in a completely different way compared to the original story. For example, he could be taught by the gods to control elements at a very young age.
Harry would probably be more aggressive in his personality. Vegeta's Saiyan nature is often associated with a certain level of aggression and competitiveness. So, Harry might show these traits more, not shying away from a fight and always striving to be the best in any magical situation.
His personality would likely be more cold and calculating. He'd be used to getting his way through underhanded means taught by the villains.
His personality would probably be more aloof. Since basilisks are solitary creatures, Harry might not be as sociable as in the original story.
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.