If Loki were to enter the Harry Potter world, it could significantly disrupt the plot. His ability to deceive and manipulate could lead to many characters making wrong decisions. For instance, he could trick Dumbledore into believing a false prophecy, which would send Harry and his friends on a wild goose chase.
Loki's mischievous personality could make Harry more adventurous. Harry might start to take more risks in his magical studies and in facing Voldemort. For example, he could be more willing to try out untested spells or strategies.
One idea could be that Loki, being the mischievous character he is, finds his way into the wizarding world of Harry Potter. He could start causing chaos in Hogwarts, perhaps by disguising himself as a student or a professor and playing pranks that are far more elaborate than those of the Weasley twins. For example, he might turn the entire Great Hall into an ice rink during breakfast time.
It can also taint the positive image of the 'Harry Potter' fandom. Outsiders might get a wrong impression that the fandom is associated with promoting or at least tolerating such disturbing content, which is not true for the majority of the fans who love the series for its positive values like friendship, courage etc.
Loki is a powerful Asgardian with abilities that are more in the realm of the supernatural in a different way than Harry's magic. But Harry has a strong will and has faced some extremely tough opponents. In a fanfiction, if the writer decides to give Harry access to some of the most powerful and ancient magic in the wizarding world, he could be more powerful. For example, if he could use the magic that created the Hogwarts itself, he might be able to stop Loki quite effectively. Also, Harry has the support of his friends and the entire wizarding community behind him, which could give him an edge in power.
It's hard to say. Loki has a wide range of magical abilities from Asgard. He can shape - shift, create illusions, and has a certain level of telekinesis. However, Harry Potter has the power of love and friendship on his side, which has proven to be a very strong force in his world. Also, Harry is very skilled at defensive and offensive magic within the wizarding world. So it really depends on the situation.
The 'misery crossover' often changes the relationships between characters. A character with a tragic past may be more guarded and less likely to trust the friendly and open - hearted characters in the Harry Potter series. This mistrust can lead to a lot of drama and new storylines. Also, their different values due to their past miseries can drive the plot in unexpected directions. For example, a character from a world where survival is the only goal may see the use of magic for fun or minor tasks as a waste, and this could cause arguments and division among the characters.
At the beginning, Harry would be frightened. He's in an unknown place with Loki, who is known for his trickery. But Harry is no pushover. He would quickly gather his courage. He would remember all the times he's faced danger at Hogwarts. He might try to communicate with Loki to understand his motives. If Loki reveals that he wants to use Harry's magic for something, Harry would try to find a way to outsmart Loki. He could pretend to cooperate while actually looking for a weakness in Loki's plan. Harry would also be thinking about his friends at Hogwarts and how he needs to get back to them, which would give him extra motivation to fight back against Loki.
It can create some division. Some fans who love the original series might be offended by the bashing. But on the other hand, it can also bring in new perspectives. It might make people think about the characters and the world in different ways, even if those ways are critical.
The magic in Harry Potter could give the RWBY pets new abilities. For example, they might be able to fly using magic spells or become invisible. This would change the way the RWBY characters interact with their pets and also how they use them in battles. The pets could also gain the ability to communicate with the characters in a more complex way, like using telepathy which is common in the Harry Potter world for some magical creatures.
It could change the plot drastically. Q has the power to manipulate reality, so he could change the fates of characters in the Harry Potter world. For example, he might save some characters who were supposed to die or create new challenges for Harry that are not part of the original story.