The main characters would be Danny Phantom in dual incarnations. One Danny is the well - known character from the original series, and the other is the product of a fan's imagination. Valerie Gray could also be a main character. She might be caught in the middle of the two Dannys' meeting, not sure which one to trust or side with. Also, the ghost dog Cujo could be there, adding some comical relief while also being a factor in the overall plot as the two Dannys figure out how to handle his presence in their strange encounter.
Obviously, the main character would be Danny Phantom himself, but in two different forms or versions. One would be the original Danny Phantom from the canon source, and the other would be a version created by the fanfiction. There might also be his friends like Sam and Tucker who could play important roles in helping the two Dannys understand each other and deal with any issues that arise from their meeting.
I think Superman would be the most likely. Superman is known for his kind heart and open - mindedness. He would probably see Danny as a young hero in need of some guidance and friendship. He wouldn't be too quick to judge Danny based on his ghostly appearance or powers.
In this fanfiction, it could be that Danny Phantom meets a Danny Phantom from a parallel fan - made story. At first, they don't trust each other. But as they learn more about each other's worlds, they realize that there are some common elements that are being threatened. It could be that a powerful ghost is trying to rewrite all the fanfic universes related to Danny Phantom. So, they must combine their strengths and knowledge to stop this from happening.
In a crossover, characters from the other franchise might betray Danny. For example, if it's a crossover with a show about vampires, a vampire character who seems friendly at first could betray Danny for his ghost powers. They might want to use his powers for their own dark purposes. Another likely candidate could be a character who is jealous of Danny's abilities. Maybe in a crossover with a superhero world, a sidekick who feels overshadowed by Danny's powers and popularity might be the one to betray him.
In addition to the ghosts, there might be some human characters that are important in the 'phantom city danny phantom fanfiction'. They could be Danny's friends or family members who get involved in the events of the Phantom City. Their reactions to the supernatural world and their interactions with Danny and the ghosts would add an interesting dynamic to the story.
Obviously, Danny Phantom and Ember would be the main characters. Danny is the half - ghost protagonist who is being raised by Ember. Ember, a ghost with music - related powers, would play the role of his caretaker or mentor in this fanfiction.
Sam is also quite popular. Her goth - like personality and her strong - willed nature make her an interesting character. In fanfiction, she can be portrayed in different ways, like being even more involved in Danny's ghost - fighting activities.
Obviously, Danny Phantom and Dan Phantom are the main characters. Danny is the original form, a heroic character, and Dan is his more evil and powerful transformation.
Danny Phantom is for sure the main character on the saving side. On the Justice League side, all the classic members would probably be there. Superman, being the symbol of hope and having super strength, heat vision etc. Batman, the Dark Knight with his gadgets and detective skills. Wonder Woman with her Lasso of Truth and superhuman strength. The Flash, who can move at incredible speeds. Green Lantern, who can create constructs with his power ring. And Martian Manhunter, with his shape - shifting and telepathic abilities. They all could be in danger and Danny would have to figure out how to save each of them based on their unique powers and vulnerabilities.
Obviously, Danny Phantom himself. And his classmates, which could include Sam and Tucker. They are Danny's closest friends and are likely to play important roles in the story.
Obviously, Danny Phantom is one of the main characters as the title implies he's the one doing the pranking. And then, members of the Justice League like Superman, Batman, Wonder Woman, Flash, etc. would be the ones being pranked.