The character's perspective changes drastically. They no longer take the magic for granted as they did in their first 'life'. They might be more cautious about using magic, especially if they remember the consequences of misusing it from their past life. They also might look at the Death Eaters not just as villains but as products of a flawed society, and try to reform rather than just defeat them, which is a very different approach compared to the original characters in the Harry Potter series.
The reincarnation makes the character see the wizarding world with fresh eyes. They might notice things that were overlooked in the original story. For example, they could see the flaws in the Hogwarts education system more clearly.
It changes the story by introducing an element of mystery. Since the oc is reincarnated, there are questions about their past life and how it will impact the present in the Harry Potter universe. For instance, they might have a connection to a long - forgotten magical artifact from their past life.
In fanfiction, Harry Potter can change the Wizarding World in many ways. For example, he might introduce new spells or magical concepts that were not in the original series. He could also have different relationships with other characters, which in turn would affect the social dynamics of the Wizarding World.
The reincarnation can completely change the relationships. For example, if Harry is reincarnated, he might not have the same bond with Ron and Hermione. He could form new friendships that were not possible in the original story.
His character might become more family - oriented. Since Arthur was very much a family man, Harry could start to value family bonds more. He might also develop a new - found interest in Muggle artifacts like Arthur had. And he could become more diplomatic in his approach to different situations, as Arthur was known for his level - headedness.
Well, Harry's immortality would bring about a great change in the wizarding world. Since he can't die, he could be a source of hope for a very long time. He might inspire new generations of wizards to be braver. Also, the way magic is used and perceived could change. For instance, people might study his immortality to find ways to extend life in general. And his influence on the fight against dark forces would be continuous, not just a one - time deal like in the original story.
His perspective could expand. He might start to consider new possibilities within the wizarding world. For example, if a fanfiction introduced a new relationship between a Fantastic Beast and a wizard, he'd think about how that could work in the real wizarding world.
The plot would change a great deal. For one, Harry would be much more powerful physically. So when facing Voldemort, he could use Thor's strength in combat, not just rely on magic. He might be able to take on Death Eaters more easily.
Well, it completely changes the setting. Instead of Hogwarts and the wizarding world of Britain, he's now in Kuronu. This means different magical rules, different cultures, and different relationships. His skills and knowledge from the Potter world may or may not be applicable in Kuronu.
Sasuke's adaptation would be a long process. He'd start by observing the daily lives of wizards. He'd notice how they use magic for simple tasks like lighting candles or cleaning. In contrast, in his past life, he'd use ninjutsu for such things. He'd have to get used to the fact that he can't just rely on his Sharingan all the time. He might attend classes at Hogwarts and learn about different spells. At the same time, he'd be constantly comparing the magic here to his ninja skills. As time goes on, he'd start to blend in more, using magic in his own unique way that combines his ninja - like thinking.
Naruto's character might become more serious. Izuna was a more solemn character compared to Naruto's usually upbeat self. So, Naruto could start to show less of his goofy side and more of a calculating nature. He might also become more attuned to the Uchiha's way of thinking, which could lead to some friction with his old friends who are used to the old Naruto.