Well, he might accidentally bring some of the dark forces from his world to Remnant. Or, on the other hand, he could bring new hope and ideas to fight the existing threats in Remnant. His presence could also cause some political unrest as the different factions in Remnant might try to use him for their own gains. And of course, his own journey of self - discovery would be completely different in this new world.
Well, he might find a whole new world of magic and powers in Remnant. Maybe he'd meet new characters and form alliances. He could also introduce some of his own magic techniques to the people there.
Well, he might find a whole new world of unique Grimm creatures in Remnant. Maybe he'd use his magic in ways that the people there have never seen before, causing both amazement and a bit of fear. He could also meet new allies and enemies, and his journey could be about trying to find a way back home while also getting involved in the local conflicts of Remnant.
He might gain some extraordinary magical abilities. For example, he could be able to control time or have a deeper understanding of magic spells that were previously difficult for him.
He'd probably start by trying to understand the new world around him. He'd observe how people interact, how the society functions, and what the threats are. For instance, learning about the Grimm and how they operate would be crucial for his survival.
His friends could be disappointed in him. In the original story, the Yule Ball was something that his friends were looking forward to, and if he doesn't go in the fanfiction, they might feel let down. This could lead to some strain in their relationships. Additionally, not going to the ball might mean that Harry doesn't get to show off his dancing skills (if he had any in the fanfiction), and he might lose some popularity among the students who were expecting to see him there.
She might face some magical backlash. Saving someone from the veil could be against the natural laws of magic in the fanfiction world, so she could experience some physical or mental exhaustion as a result.
In the 'Harry goes through the veil fanfiction', Harry may face a great deal of danger. The veil is often associated with death in the wizarding world. So, perhaps he has to fight off dark forces that lurk on the other side. He might also have to find a way back to the living world, which could involve solving puzzles or making difficult choices. There could be a new set of magical rules there that he has to learn quickly in order to survive.
He might get confused. Fanfiction often takes the original story in different directions, with different characterizations and plot twists. If Harry reads it, he might start to question the 'true' nature of his own experiences and the people around him.
One consequence could be that he endangers himself. Maybe he disobeys a warning not to enter a certain dark forest in the fanfiction. As a result, he could encounter dangerous magical creatures or dark wizards. Another outcome is that his disobedience might lead to a rift in his relationships. If he doesn't follow the advice of his mentors like Dumbledore in the fan - made story, it can cause tension between them.
A possible plotline in such fanfiction could be that the veil is not just a one - way passage to the afterlife. Instead, it's a sort of limbo where Harry Potter is trapped. He discovers that there are other lost souls there, some of which have been there for centuries. Harry then tries to find a way to free all of them, not just himself. This could lead to him learning about the true nature of death and the veil in the wizarding world, and perhaps he even has to make a deal with some dark forces within the veil to achieve his goal.