I don't know for sure. But probably Harry himself would be a main character. And he might meet some well - known Pokemon characters like Pikachu or Ash.
Well, if it's based on the idea of Harry in the Pokemon world, he would be one of the main characters. There could also be a special Pokemon that he befriends early on, like a Charmander or Eevee, which would also be a main character in the story. Maybe there are some other trainers or Pokemon experts in the fanfiction that play important roles as well.
Since it's Harry's Pokemon fanfiction, Harry is bound to be a central figure. He could encounter other original characters created specifically for this fanfiction. There could be a group of misfit Pokemon that he takes under his wing. These Pokemon and their unique personalities would also be main characters. And perhaps there's a villain in the story, someone who wants to disrupt the balance in the Pokemon world, and they would be another key character.
Obviously, Harry would be the main character as the title says he's the one who finds the Pokemon egg. His friends Hermione and Ron would probably be important characters too. They are always by Harry's side in most of his adventures in the wizarding world, so it's likely they'll be involved in this strange new discovery as well. And, of course, the Pokemon that hatches from the egg would also be a key character.
Obviously, Harry Potter would be one of the main characters. And maybe Hermione, since she's always interested in new and strange things. Also, a Pokémon like Pikachu could be a sort of main character in its own way, as it's the iconic Pokémon.
The villains in the fanfiction can also be considered main characters in a sense. They might be after the power of the legendary Pokemon. There could be a team of bad guys who are trying to capture and control a Groudon or a Kyogre to cause chaos in the Pokemon world, and Ash has to stop them. Their actions and plans create the conflict that Ash has to overcome in the story.
Obviously, Ash is one of the main characters. Since it's about him being a legendary Pokemon in this fanfiction, he's central to the story.
Obviously, Nyssa is a main character. She is likely to be the central focus of the story, driving the plot forward with her actions and decisions. Another main character could be her first Pokemon, which she has a special bond with. This Pokemon might be her constant companion throughout her adventures.
There might be other trainers in the fanfiction. They could be friends or rivals to Elaine. A rival trainer could constantly challenge Elaine to battles, pushing her to improve. And her friends could join her on adventures and offer support when she faces difficulties.
Obviously, Sawyer is a main character. But there could also be his Pokemon as important characters. Depending on the story, other trainers he meets during his journey might also be main characters. For example, if it's a story about a big tournament, the opponents he faces could be main characters too.
Obviously, Nate is a main character. His Pokemon are also important characters in the fanfiction. Depending on the story, there might be other trainers that Nate meets during his journey, like a rival trainer who constantly challenges him.
Well, obviously Fennel is one of the main characters. She is often the center of the story due to her role as a researcher. Sometimes, the main character from the Pokemon games might also be a main character in the fanfiction, interacting with Fennel and helping her with her research or getting help from her in their own Pokemon journey.
I'm not sure specifically as it depends on the particular fanfiction. It could be a young trainer with a special dragon - type Pokemon like a Charizard or Dragonite.