Obviously, Harry Potter would be one of the main characters. He is the one who finds the One Ring after all.
I think Frodo Baggins could also be a main character. Since it's his ring originally, he might show up to help Harry understand what the ring is all about and the great danger it poses. And of course, Dumbledore could be in it too. Dumbledore, with his great wisdom, would surely offer some insights to Harry regarding the One Ring, and how it compares to the dark magic they've faced in the wizarding world.
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.
Definitely Voldemort and Sauron. Voldemort would see the One Ring as a powerful tool to conquer the wizarding world completely. Sauron, on the other hand, would not want anyone else to have control over the ring. So they would both be after Harry and the ring, making them the main antagonists.
Obviously, Harry would be one of the main characters since it's in his name. His friends like Hermione and Ron would probably also be in it. They often accompany Harry on his adventures. And there could be some antagonists as well, maybe some dark wizards or magical creatures that try to stop Harry from finding his energy core.
Well, perhaps Harry uses his magic to sense the One Ring's power. He might initially mistake it for a dark magical artifact from his own world. Then, he could start on a journey to figure out what this strange ring is, all while facing challenges from both the wizarding world (like Voldemort's followers thinking he has a new powerful weapon) and from Middle - earth forces that are also after the ring.
One possible plotline could be Harry's initial confusion when he stumbles upon the One Ring. He might wonder about its strange power and how it seems to call to him in a way different from magic he's used to.
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.
The 9th doctor is sure to be a main character. Since it's about him finding a Time Tot, he'll be the one driving the story forward, making decisions, and facing challenges. The Time Tot itself will also be a main character. It might be a source of mystery and wonder. There could also be other characters like the doctor's companions if the fanfiction decides to bring them in. They could offer different perspectives and help the doctor in his quest related to the Time Tot.
Obviously, Harry would be the main character. Since it's about him being a Saiyan. And I think some of his friends from the Harry Potter series might also be important characters, like Hermione and Ron. They could react to Harry's new Saiyan identity in different ways.
Obviously, Harry would be the main character as the title implies. But other characters like Hermione and Ron would also be important. They could either be part of Harry's regime, reluctantly or wholeheartedly, or they could be part of the resistance against his dictatorship.
Obviously, Harry would be the main character. Since it's about him being a playboy, he would be at the center of the story. There might also be his friends like Ron and Hermione. They could play important roles in either supporting or trying to change Harry's playboy ways.