Well, the main character could be a Muggle - born wizard who has always felt a bit out of place in the wizarding world. Traveling through the Harry Potter world would be their way of really understanding and finding their place in it. Or it could be a time - traveling character, perhaps a future wizard who comes back to the time of Harry Potter to study the magic of that era. They could get involved in various adventures during their travels. Also, a group of international exchange students could be the main characters. They would travel around the wizarding world, comparing and contrasting their different magical cultures.
The main characters might include some of the minor characters from the original series. For instance, Neville Longbottom could be one of the main characters. If he has a special kiss with a character, perhaps Luna Lovegood, it could change his confidence level and give him some new abilities or powers that then change the world. Also, it could be an older character like Dumbledore, if the fanfiction has a time - travel or magical - memory - related plot where a kiss from the past or future involving Dumbledore has a world - changing impact.
Most likely, Harry Potter himself would be one of the main characters. He has a natural inclination for adventure and would be eager to explore the world on the train. Hermione Granger would also be there, with her vast knowledge of magic to help them out in different situations. Ron Weasley too, for his loyalty and friendship.
Obviously, Harry Potter himself would be the central character. He would be the one driving the story forward with his actions and decisions.
Harry Potter himself could be a main character. He might use time travel to gain more knowledge about his parents or to change some of the events that led to their deaths.
Obviously, Harry Potter himself would be the central character. His friends like Hermione and Ron would probably also play important roles. They might be his advisors or the ones helping him carry out his plans. Dumbledore could also be a significant figure, even if only in spirit or through flashbacks, guiding Harry's actions as he tries to take over the world.
Obviously, Harry Potter himself is the central character. Hermione Granger and Ron Weasley are also likely to be involved as they are his closest friends. They might assist Harry in his quest to conquer the world in different ways, like Hermione providing the knowledge and Ron being the loyal support.
Ron Weasley can also be a main character in such fanfiction. His loyalty to Harry and his own experiences in the original story can add depth to the time - travel redo plot. He could be the one to provide emotional support or come up with unexpected solutions during the time - travel adventures, even if he may not be as well - versed in the technicalities of magic as Hermione.
Harry Potter himself is often a main character. He might use the time travel necklace to gain more knowledge about his parents or to find a way to defeat Voldemort more effectively.
A descendant of one of the original founders of Hogwarts. They might have some special connection or mission related to the school and the wider wizarding world. They would travel around to uncover secrets about their family's past and the history of the magical places.
Hermione could be a main character. As a very intelligent witch, she might assist Harry in his teaching, like helping him prepare complex lessons or providing additional knowledge to the students. For example, when Harry is teaching about ancient spells, Hermione could offer insights from the books she has read.