Skeletor could be a major character as well. Knowing He - Man's true identity could give him new ideas for his evil schemes, and he would be a central antagonist in the fanfiction.
Well, obviously He - Man himself is a main character. His alter - ego, Prince Adam, would also play a crucial role as the identity that has been revealed.
Teela is likely to be an important character. As someone close to He - Man, she might be involved in how the revelation affects their relationship and the kingdom.
Perhaps Doctor Octopus. Knowing who Spider - Man really is, he might use his intelligence and his mechanical arms to create elaborate traps for Peter Parker at his home or workplace. He could also try to expose Spider - Man's secrets further to the public and turn the public against him.
There could also be other important characters like Alya, Marinette's best friend. She might play a role in helping the two heroes adjust to the new situation. Maybe she helps keep their secret or gives them advice on how to handle their new relationship. And then there are the villains, such as Hawk Moth, who are still important as they continue to pose a threat to Paris even after the identity reveal.
Obviously, all of the Avengers would be affected. But characters like Iron Man/Tony Stark would be a big focus. His playboy billionaire image could be completely changed in the public eye once his superhero identity is out. Also, Spider - Man if he's part of the Avengers in the fanfiction. His young age and normal life with Aunt May would be greatly disrupted.
One interesting plotline could be He - Man's friends' reactions to his revealed identity. They might have mixed feelings of shock, but also a deeper understanding of his burdens.
In addition to Danny and his immediate circle, there could be other characters from the Danny Phantom universe. For example, Valerie Gray. If she discovers Danny's identity, she might have a complex reaction. On one hand, she's been hunting ghosts, but on the other, Danny has also been protecting the town. So, her role in the fanfiction could be very interesting, especially in terms of how she interacts with Danny after the identity reveal.
Obviously, Ladybug and Chat Noir are often central. Marinette, who is Ladybug, and Adrien, who is Chat Noir. Also, Hawk Moth as the main villain often plays a role in these fanfictions when the identity is about to be revealed or has been revealed, as his actions can be related to this big event.
Obviously, Batman/Bruce Wayne himself is a central character. His life would be turned upside down by the revelation of his identity.
Obviously, Danny Phantom himself is the central character. His friends like Sam and Tucker are also often involved. They play important roles in how Danny deals with his revealed identity, either by providing support or getting into trouble because of it.
His best friend could be the one. Since they are close, they might notice some strange behavior or coincidences that lead them to suspect Peter is Spider - Man. For instance, Peter always disappearing at the same time Spider - Man shows up.
His friends like Mary Jane and Ned Leeds could also be main characters. They often play important roles in Spider - Man's life, whether it's providing emotional support or getting involved in his superhero activities. In this fanfiction, they might be more deeply involved in the secrets that are being revealed, such as helping Spider - Man deal with the consequences of a particular secret getting out.