In addition to the main trio from Harry Potter, Dumbledore could also be a major character. His wisdom and powerful magic could be crucial in dealing with Godzilla. He might be the one to come up with a plan to either communicate with Godzilla or find a way to send it back to its own world. On Godzilla's side, there could be some sort of a magical connection or entity that is controlling it or has a link to it, and that could also be considered a main character in the fanfiction.
Definitely Dr. Alan Grant. He has so much knowledge about dinosaurs that he could be the key in trying to understand how Godzilla affects the dinosaurs in the park. Also, Godzilla himself would be a main character in a sense. His actions and presence would drive the story. And maybe Claire Dearing, as she has experience managing the park and could be involved in the efforts to either protect the park from Godzilla or figure out how to co - exist with him.
Definitely the Eva pilots, Shinji, Asuka, and Rei. They are the main characters in Evangelion and would be at the forefront of dealing with Godzilla's appearance in their world.
Harry Potter and Simba would likely be main characters. Harry with his magic skills and Simba with his leadership in the Pride Lands could team up for some great adventures.
Obviously, the female version of Harry Potter and Merida would be the main characters. They would be at the center of the story, driving the plot forward with their actions and decisions.
Well, one possibility could be that Godzilla somehow ends up in the wizarding world. Maybe a powerful dark magic spell goes wrong and creates a portal that sucks Godzilla in. Harry and his friends at first think it's a new kind of dark creature created by Voldemort. They try to fight it using spells, but soon realize that Godzilla is not exactly evil. Godzilla might then start causing destruction in Hogwarts, and the wizards have to figure out a way to either send it back or control it without killing it.
Lex Luthor from Supergirl's world could be the villain. He could somehow find a way to travel to the wizarding world and team up with some dark wizards. He wants to use magic to enhance his power and take over both worlds. Supergirl and Harry Potter would have to stop his evil plans.
Yang would be a likely character. She's bold and not one to back down from a challenge. She might see Godzilla as a huge opponent to test her strength against. Maybe she'd start off trying to punch it, only to realize that brute force alone won't work and then have to figure out a more strategic way to interact with it.
One interesting pairing could be Godzilla and Hulk. Both are powerful, almost indestructible forces of nature. They could have an epic battle at first, as they both have a tendency to lash out when provoked. But then they could end up teaming up against a greater threat, like a powerful alien invasion. Another great pairing would be Godzilla and Iron Man. Iron Man could use his technology to study Godzilla, and perhaps even try to create some sort of armor inspired by Godzilla's abilities. And Godzilla could provide a physical presence that Iron Man could rely on in a fight. Also, Godzilla and Thor could be a fascinating pair. Thor's god - like powers and connection to nature could be paralleled with Godzilla's own primordial power. They might have a mutual respect for each other's strength.
Shinji would probably be terrified at first. He's already hesitant and scared in his normal battles, and Godzilla is much larger and more intimidating than the Angels he usually faces. Asuka would likely be more aggressive, thinking she can take on Godzilla with her Eva. Rei, on the other hand, would be very calm and observant, trying to understand Godzilla's nature. Misato would be in a panic initially, but then quickly start strategizing on how to deal with this new threat. Gendo would see Godzilla as either a new opportunity or a major obstacle depending on his long - term plans.
Obviously, Harry Potter would be one of the main characters. He could be the one to bridge the gap between the wizarding world and the Transformers. Optimus Prime could also be a main character. His leadership and sense of justice would make him a great ally for Harry in the fight against evil. Hermione would also play an important role, using her intelligence to understand the Transformer technology and magic combination.