Paul is the key figure around which the story revolves, despite his death. Then there are his closest Pokemon, which could be main characters as they might have unique reactions to his passing. Characters like his family members, if they exist in the fanfiction, would be main characters as well. They would be dealing with the loss and might be involved in any investigations if there are suspicions around his death. Also, trainers who looked up to Paul or had a rivalry with him would be in the spotlight, as they would have to come to terms with his absence and how it affects their own Pokemon - training journey.
Obviously, Paul would be a central character, even though he's dead. His friends and rivals are likely to be main characters too. For instance, Ash, who has interacted with Paul multiple times, would probably play a significant role. His Pokemon could also be important characters in a way, as they are left without their trainer. Other trainers in the Pokemon world who knew Paul, like Dawn or Brock if they had a connection to him, might also be main characters as they deal with the aftermath of his death.
Obviously, Paul himself is the central character. His brother Reggie might also appear as he could be concerned about Paul's condition and offer support. Ash could be in it too. He might be someone who initially doesn't get along with Paul but then shows compassion because of his illness. And of course, Paul's Pokemon would be there, like his Torterra or Electivire.
Paul Blofis himself would be one of the main characters. His immediate family members like his wife and children would also be important. Maybe his parents or siblings would be there too.
The Pokemon themselves can also be considered important characters in a way. They are not just companions but also a big part of the world. Their battles and interactions can mirror or influence the relationship between Ash and Paul. For example, if Paul's Chimchar evolves during a battle against one of Ash's Pokemon, it could be a turning point in their relationship.
Obviously, Ash would be the main character since he's the one collapsing. His Pikachu would most likely be a key character as well. Pikachu is always by Ash's side and would probably be very concerned and try to help when Ash collapses.
It could be two elegant - looking Pokemon like Gardevoir and Milotic. Gardevoir has a very graceful appearance and psychic powers, and Milotic is known for its beauty and elegance in the water.
Most probably, the main characters would include enthusiastic trainers of different ages. There might be a budding trainer who is shy but has a very powerful Pokemon. Another could be an experienced trainer who acts as a mentor to the younger ones at the camp. And of course, there could be a mischievous trainer who always gets into trouble but has a heart of gold.
Most likely, there will be trainers. They could be young and enthusiastic about Pokemon. For example, a boy trainer who has been on a long journey and finally meets his childhood friend who is also a trainer.
The tailed beasts could potentially play a role too. Maybe they are somehow connected to the race, like being the power source for certain obstacles. And Kurama, being inside Naruto, could give him an edge in the race by providing extra chakra or unique abilities.
Obviously, Paul and Percy are going to be main characters. Paul, as the one who finds out Percy's big secret. Percy, being the demigod whose secret is revealed. And there could also be other characters from the Percy Jackson series like Annabeth. She might be involved in helping Percy deal with Paul's discovery, either by giving advice or by being there to support Percy emotionally.
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.