The Leviathan could disrupt Harry's Animagus ability. If the Leviathan has some sort of chaotic or powerful magic, it might interfere with Harry's ability to transform at will. He could find himself transforming unexpectedly or not being able to transform when he needs to. On the other hand, it could also force Harry to master his Animagus ability more quickly. For instance, if he has to use it to escape from the Leviathan, he would have to learn how to control it better.
In fanfiction, the presence of the Leviathan could create a whole new set of challenges for Harry's Animagus ability. The Leviathan might have the power to influence the magic that governs Animagus transformations. This could mean that Harry has to find a way to counter this influence. Maybe he needs to seek out a special spell or potion to keep his Animagus ability stable. Or perhaps he has to form a magical bond with another creature that is immune to the Leviathan's influence in order to maintain his Animagus form.
His Animagus ability might be enhanced. The danger posed by the Leviathan could make Harry more in - tune with his magical side. For example, if his Animagus form is a stag, he might become faster or more powerful in the presence of the Leviathan. It could also be that the Leviathan has a certain magical aura that affects Harry's transformation. Maybe it makes it easier or more difficult depending on the situation.
The more combat - oriented Avengers like Captain America would see it as a useful tool in battle. He could strategize on how to best utilize Harry's ability. For instance, Harry could transform into his animal form to scout ahead or create distractions during a fight against a powerful enemy. Steve would appreciate this new element in their fight against evil.
One interesting concept could be Harry Potter's Animagus form interacting with the Leviathan. Maybe his Animagus form is a small creature like a mouse, and it has to find a way to communicate or avoid the Leviathan. Another idea is that the Leviathan has some sort of magical connection to Harry's Animagus ability, like it can sense when he is in that form. Also, perhaps Harry uses his Animagus form to explore a hidden world where the Leviathan resides, and discovers secrets about the wizarding world that were previously unknown.
The fandom would be divided. Some fans who are deeply into fanfiction would be disappointed and might feel like a part of their connection to the 'Harry Potter' world has been cut off. However, others who are more focused on the official works might not be as affected. There would likely be a decrease in the variety of fan - created stories, which could limit the creative exploration within the fandom.
Hermione would probably be both fascinated and a bit exasperated. Fascinated because Tigger is such an unusual creature, but exasperated because his bouncy antics might disrupt her study time. Ron would likely be amused at first, thinking Tigger is a great source of entertainment. He might try to get Tigger to do tricks for him. Harry, on the other hand, would be more cautious. He would see Tigger as a potential ally or a new responsibility. He would want to make sure Tigger doesn't get into too much trouble or put himself in danger in the wizarding world.
Dumbledore would be very cautious. He would likely sense the great evil in Palpatine immediately. He would start to research and try to find a way to neutralize the threat. Hermione would be intrigued and start reading every book she could find about this strange new figure. Harry, on the other hand, would be more instinctive. He would feel the danger and be ready to fight if necessary.
It would completely change the nature of the story. Harry Potter is seen as a hero, and this act would make him a villain. It would be a huge deviation from the original story's positive values.
Dumbledore could be his mentor. He has vast knowledge and experience, and he would likely see the potential in Harry being an Animagus. He could guide Harry through the difficult process of learning to control his transformation and use his Animagus form for good.
His relationships would likely be in turmoil. His friends might notice a change in Harry and be confused. Loki could make Harry act distant or say strange things to Ron and Hermione, causing them to worry. And his relationship with Ginny might also be affected as Loki might make Harry act in ways that Ginny doesn't understand.
First of all, Harry could offer the orphans protection. If there were any threats from the wizarding world or even from the Muggle world like bullies or bad caretakers, he could step in. He would also introduce them to a world of magic, which would be a huge change. They might start to see things in a different way, with more wonder. He could also use his influence to get better resources for the orphanage, like new clothes, better food, and educational materials. This would not only improve their living conditions but also give them a better start in life. And on an emotional level, his friendship and support would mean a lot to orphans who might not have had much of that before.
Hermione, as an Animagus (in this fanfiction), might approach the situation more intellectually. She would first study the Wendigo, trying to understand its nature and origin. Maybe she would research in the Hogwarts library to find any spells or potions that could either calm the Wendigo or protect herself and others from it. She could also use her Animagus form to get closer to the Wendigo without being detected easily.