Harry Potter is the central figure. Then, the 'charmed one' which could be a previously unknown character or a new take on an existing character from the Harry Potter universe. There might also be antagonists. Maybe some dark wizards who want to use Harry's connection to the charmed one for their evil purposes. And of course, Dumbledore or other Hogwarts professors might play important roles as they often do in stories related to Harry, guiding him and helping him understand his new situation.
Definitely characters from both 'Charmed' and 'Harry Potter'. From 'Harry Potter', Harry, Hermione, and Ron are very likely to be main characters as they are the central figures in the original series. In 'Charmed', the Halliwell sisters, Prue, Piper, and Phoebe, would be prime candidates. Their different powers and personalities would create interesting dynamics when interacting with the 'Harry Potter' characters.
There could also be other characters from the Harry Potter universe like Hermione and Ron. They might be involved in helping Harry navigate this new world of being connected to the Charmed Ones. And from the Charmed side, there could be Leo, their Whitelighter, who might have some interesting interactions with the magical folk from Harry's world.
Often, in such fanfiction, new original characters are introduced. They could be the ones who created the charmed lemon in the first place. But it's also possible that characters like Dumbledore could play a significant role. He might know more about the charmed lemon than he lets on and be guiding the other characters from behind the scenes. Neville could also be a main character, using his skills with plants to take care of the charmed lemon or study it.
It could be about a story where Harry Potter is the son of a person who is charmed in some way. Maybe this 'charmed one' has some special powers or a unique background that influences Harry's life in the fanfiction world. It might explore new adventures, relationships, or powers that Harry has because of his connection to this 'charmed one'.
Harry Potter is a given. In addition to him, I think there could be other characters from the Harry Potter series who might also make an appearance. From the Charmed side, apart from the Halliwell sisters, characters like Leo Wyatt could be important. Since it's a fanfiction that combines two universes, it might also introduce new characters that are created specifically for this story to bridge the gap between the two worlds. For example, a character who has knowledge of both the magic in the Harry Potter world and the power of the Charmed ones.
There could be a really interesting fanfiction where the magical worlds of Charmed and Harry Potter collide with Harry and Maggie. Maybe they team up to fight a new kind of dark magic that threatens both their realms. They could each bring their unique magical abilities to the table. Harry with his wizardry from Hogwarts and Maggie with her powers as a Charmed one.
Hermione is often a popular crossover character. Her intelligence and magical knowledge make her a great fit in the Charmed universe. She can easily adapt to new magical situations and offer her unique perspective.
Well, Harry Potter would be one of the main characters since it's about him being the son of Bellock. And likely, characters like Hermione and Ron would still be important as they are his friends in the original series and would likely play a role in this new version of his story.
Obviously, Harry Potter would be one of the main characters. Since it's about him being the son of Tartarus. And probably his friends like Hermione and Ron would also be important characters as they are in the original series. They might react differently to Harry's new identity.
The main character is Harry Potter. His friends Hermione and Ron are likely to be main characters as well. There may be some antagonists from the Titan realm who oppose Harry because of his potential power. There could also be some other Hogwarts students who get involved in Harry's journey to discover his true identity as the son of Atlas. And perhaps an old wizard who has knowledge about the connection between the wizarding world and the Titans and helps Harry along the way.