One possibility is that Harry's late arrival at Hogwarts could change the dynamics of the relationships he forms. For instance, instead of being in the same boat as the first - years from the start, he might end up befriending some older students who take him under their wing. Also, his late start could mean that he discovers parts of Hogwarts that others haven't yet, like secret passages or rooms that are only accessible to those who arrive late or are in a certain situation.
In the fanfic, if Harry Potter goes to Hogwarts as a vampire, he could face discrimination. Vampires are often seen as dark creatures in the wizarding world. He might be isolated from his friends like Ron and Hermione. His appearance would also change. He'd have pale skin and fangs, which would be quite different from his normal look. Magic at Hogwarts might affect him differently too. Spells that are harmless to normal wizards could be more or less effective on him. He'd need to find a way to control his thirst for blood. If he couldn't, it could lead to chaos at Hogwarts. Maybe he'd have to find a substitute for blood, like some kind of potion.
There could also be some new characters introduced. Maybe a student who also had a late start in a previous year and can give Harry some advice. Or a magical creature that Harry encounters on his way to Hogwarts late and that creature becomes some sort of guide or protector for him during his time at Hogwarts.
It would be a really interesting scenario. Maybe the characters in Hogwarts would get inspired by the fanfiction they read. For example, they could learn new spells or magical concepts from it. They might also be amused or confused by the different interpretations of their own world in the fanfiction.
He might use his spider - powers to outperform in Quidditch. His agility could make him an excellent seeker, zipping through the air to catch the golden snitch much faster than others.
In a fanfiction where Harry Potter goes to highschool, he would bring a whole new perspective. He's used to a world full of magic and mystery, and highschool would seem rather ordinary in comparison. However, his magical instincts could still come in handy. For example, he might be able to sense when someone is lying, just like he could sometimes sense the presence of dark magic. His relationships with teachers would be interesting too. Some might see him as a bit of an oddball, while others could recognize his special qualities.
Well, he might be really confused at first. Equestria is a very different world from the wizarding world he's used to. He'd probably be amazed by the magic there which is so different from his own. The ponies might be a bit scared of him initially, thinking he's some kind of strange new creature. But as time goes on, he could start to learn about their ways and maybe even use his wizarding skills to help out in Equestria.
Well, if Harry Potter goes to Neverland in fanfiction, it would be a wild adventure. Harry is used to the rules and magic of the wizarding world, but Neverland has its own unique brand of magic. He might find that his spells work differently there. And he'd probably meet Peter Pan, who has his own set of powers. The two could either become friends or rivals as they each have their own ideas about magic and heroism.
Well, he might use his magic in ways that Camelot has never seen. Maybe he'd help King Arthur with some tough battles using spells like Expelliarmus. He could also introduce the wizards' world to the knights, which would be really interesting.
Well, he might be really confused at first. Japan has a very different culture from the wizarding world he's used to. He could encounter Japanese magical creatures that are unique to their land. Maybe he'll visit a Japanese wizarding school and be amazed at their different teaching methods and spells.
Well, he might be really confused at first. Storybrooke has its own set of magic and rules that are very different from the wizarding world. He could start exploring and find some similarities between the magic there and his own. Maybe he'd team up with some of the characters in Storybrooke to solve problems or fight against a common enemy.