Well, you might want to check out 'Harry's Double Life'. In this fanfic, Harry pretends to be a Muggle exchange student to investigate some mysterious events at Hogwarts.
Maybe Harry acts all mysterious and brooding like a typical vampire. He might also wear dark clothes and avoid sunlight to convince others he's a vampire. Another possibility is that he pretends to have vampire powers like super speed or the ability to fly.
Power and its implications are also common. If Harry has a new identity, it usually comes with different powers or limitations. Writers explore how he uses or struggles with these new powers. In some fictions, he may have to hide his powers to avoid danger, while in others, he uses them to change the wizarding world for the better.
One popular 'Harry Potter is someone else fanfiction' could be those that reimagine Harry as a different type of wizard, like a wizard from a different magical culture. For example, there might be fanfics where he is more in tune with the ancient magic of the druids.
It's appealing because it allows fans to explore different possibilities. We get to see Harry in a new light, which can be exciting.
It could be a random wizard or witch from another school. Maybe a student from Beauxbatons or Durmstrang who crosses paths with Harry before he meets Ron or Hermione. This could lead to a whole new set of adventures and friendships that change the course of the story as we know it.
Maybe it's a powerful noblewoman from within the Seven Kingdoms. A woman who has been overlooked for marriage before but has her own influence and resources. Her marriage to Robert could be a way for her to gain more power and for Robert to gain more support within his own realm.
One possible plotline could be that Harry is raised by a Death Eater in disguise. This would lead to a very different Harry, perhaps one who is more conflicted about his place in the wizarding world and has to grapple with dark magic teachings from an early age.
It means that in someone else's perspective or narrative, you are seen as the bad guy. Maybe you made a decision that affected them negatively, or they misinterpreted your actions. For example, if you got a promotion at work that someone else wanted badly, they might paint you as the villain in their story of unfairness at work.
It can happen in many ways. Maybe through words of wisdom, a selfless act, or simply being a positive role model.
They could go on an adventure to find a lost magical artifact. The two of them would have to face various obstacles, like dark creatures and complex spells set to protect the artifact.