The story would be completely different. Harry would probably have a very different personality. Instead of the somewhat shy and uncertain Harry we know, he could be more confident and assertive like Captain America. His magical abilities might be used in a more strategic way, similar to how Steve uses his combat skills. And the wizarding world would have to deal with a Harry who has a very different upbringing and set of beliefs.
The plot could change a great deal. For one, the threat of Voldemort might not be as immediate or known in the same way. Harry could be dealing with different dark forces in America, like some ancient and malevolent American - based dark wizards. His journey to discover his past and his power would likely take different turns as he navigates the American wizarding world.
His attitude towards authority might change. Captain Marvel often challenges authority when it's unjust. So Harry might be more likely to question the Ministry of Magic's decisions. For example, he might not be as hesitant to oppose Umbridge in Hogwarts.
Harry would be a more confident and brave individual. Captain America's influence would make him less afraid of challenges. In the wizarding world, he would approach his studies and the fight against dark magic with more determination. He would also be more respectful of authority, but not blindly so. If he saw something wrong with the wizarding authorities, he would try to change it in a more diplomatic way, learned from Steve's leadership.
A third concept could be that a magical object from the Harry Potter world, like the time - turner, is found in the Marvel universe. Captain America and the Avengers have to figure out how to use it. Meanwhile, Harry and his friends are searching for the time - turner in their world too. Eventually, their paths cross as they both try to understand the power of this object.
It could be really interesting. Maybe Harry would grow up with a different kind of magic education system in America. He might attend Ilvermorny instead of Hogwarts. His friends could be American witches and wizards with different cultural backgrounds and accents.
The story would be unrecognizable. His character would be different, and so would his relationships.
A really cool fanfiction idea could be that the Time - Turner from Harry Potter is used to bring Captain America to different points in the wizarding world's history. He could help in battles long before Harry Potter's time, like against Grindelwald. And in return, the wizards could offer some form of magic - based help to Captain America in his own universe, like a spell to heal his old wounds more effectively.
One great aspect of this type of fanfiction could be the character interactions. Imagine a female Harry Potter meeting Captain America. Their different backgrounds would lead to interesting conversations. Harry, with her magical knowledge, and Captain America, with his sense of justice and leadership from a non - magical world. It could create some really unique storylines.
A big part of it is the potential for character growth. Harry Potter, being female in this scenario, might have different experiences and reactions. And Captain America could learn a lot from the magical world. They could both develop in ways that are unique to this fan - created universe. For instance, Harry could teach Captain America about spells that could be useful in his battles, and he could teach her about physical combat strategies.
Well, for one thing, Harry would probably be more in touch with the old magic. Merlin has a deep connection to the roots of magic. So Harry might learn spells and techniques that have been long forgotten. His relationship with Hogwarts could also be different. Maybe he would see the school as a place to further expand on what Merlin has already taught him, rather than a place to discover magic for the first time.