I'm not sure specifically as it depends on the author of the fanfiction. But it could be three new characters created for the story. Maybe they are students at Hogwarts who discover a mysterious connection symbolized by the 'cord of three strands'.
One interesting concept could be the exploration of strong friendships, much like the trio in the original series. Maybe the 'cord of three strands' represents three characters who form an unbreakable bond.
Harry Potter is surely a main character. Ron Weasley would probably be in there too. They have always been a trio in the original series, and in this fanfiction, they could be involved in the rule of three concept. Additionally, Dumbledore might be an important character even if only in a guiding or posthumous influence kind of way, as he was very knowledgeable about magic and could have left some clues about the rule of three.
Well, the three chasers are obviously main characters. They could be new characters created by the fanfiction author, or they could be some well - known students from Hogwarts like Ginny Weasley, Demelza Robins, or even some Slytherin students who haven't had much focus on in the original series but are now given a big role in the fanfic as chasers.
Hermione Granger would still be one of the main characters. She would be by Harry's side, using her intelligence to help him understand his new powers and the implications of being the son of the 'Big Three'. She might also be researching ancient texts to find any references to such a situation in wizarding history.
Hermione and Ron would most likely be main characters. They are Harry's closest friends in the original story. Since Harry is deaged, they would play important roles in taking care of him or guiding him in some way.
Well, clearly Vionery is one of the main characters. Depending on the story, Harry Potter himself might also be a central figure, as he often is in most Hogwarts - related fanfictions. Hermione Granger could also be involved, using her intelligence to assist Vionery in her adventures or studies at Hogwarts.
In harry potter the marauders fanfiction, the main characters are the Marauders themselves. James Potter, the confident and sometimes arrogant Gryffindor. Sirius Black, the black sheep of his pure - blood family. Remus Lupin, the kind - hearted werewolf. And Peter Pettigrew, who was initially part of their tight - knit group. Their interactions, friendships, and later the events that lead to their fates are central to these fanfictions. They are often depicted in their Hogwarts days, full of youth, adventure, and magic.
Harry Potter is the mainstay, as the story is based in the Harry Potter universe. Kurama is the new element that makes it a crossover. In addition, characters like Snape could play significant roles. Snape's complex nature might lead to interesting interactions with Kurama. He could be initially hostile but then come to realize Kurama's value in the fight against the dark side. And of course, Hagrid, with his love for magical creatures, might befriend Kurama and help him adjust to the wizarding world.
Hermione Granger might also be a main character. She is an important part of the original series and her intelligence and knowledge would be useful in uncovering any truths in this fanfiction. Also, Ron Weasley could be there as Harry's loyal friend, and together they could face the challenges related to the 'truth' in the story.
Most likely Harry Potter himself would be one of the main characters. After all, it's in the title related to the Harry Potter world. And of course, the ogre would be a main character too as it's a key part of the fanfiction.