Well, the central characters are Harry and Dumbledore. But think about it, the ghosts of Hogwarts could also be part of the story. Maybe Harry gets some inspiration from the ghosts who have seen Dumbledore's actions over the years. And of course, there could be some of the Death Eaters in the periphery, as their actions and Dumbledore's counter - measures could be part of what makes Harry so angry at Dumbledore.
The main characters would be Harry and Dumbledore for sure. But it's possible that some of the other Hogwarts teachers, like McGonagall, could also be involved. She might be a witness to the confrontation, or she could be someone Harry goes to for advice before or after he tells Dumbledore off. Additionally, Snape might also play a role, as his relationship with both Harry and Dumbledore was quite complex.
The main characters would be Harry and Dumbledore. However, the antagonists could also be important. If there is a new dark force in the fanfiction, they would be the ones Harry and Dumbledore are up against. Voldemort's remaining followers could also be part of the equation. Their actions could be what drives Harry to submit to Dumbledore's leadership, as they pose a significant threat to the wizarding world and Harry realizes he needs Dumbledore's guidance to face them.
Well, perhaps Harry is frustrated with Dumbledore's secrets. Maybe he's angry about being kept in the dark regarding his own fate or the danger around Hogwarts. So he decides to confront Dumbledore and let out all his pent - up feelings.
Hermione would be a likely candidate. She is Harry's best friend and is very intelligent. She could use her knowledge of spells and magic to come up with a plan to help Harry escape. For instance, she might create a diversion or find a way to disable the security around Dumbledore's area.
For Harry, his friends like Ron and Hermione are likely to be his allies. They've always been by his side through thick and thin in the original series, so it's natural for them to support Harry in a confrontation with Dumbledore. Neville could also be an ally, given his growth and courage shown in the books.
Fred and George Weasley are very likely candidates. They are known for their love of pranks and their mischievous nature. They might see pranking Dumbledore as the ultimate challenge.
The Weasley family as a whole might also support Harry. They have always treated Harry like one of their own. Arthur Weasley, being an open - minded wizard, might understand Harry's perspective. Ginny, who is very close to Harry, would surely be on his side as well. They would see Harry as more than just a student defying a headmaster, but as someone fighting for what he believes is right.
Hermione could be a main character. She might use her vast knowledge to help Harry and Dumbledore in their adventures. For example, she could research ancient spells or potions that are crucial for their mission.
Ron would also be there for Harry. His loyalty and friendship mean he'd be by Harry's side, maybe even using his own family's magic - related knowledge to assist. And of course, Dumbledore. He has a vast amount of magical knowledge and wisdom, and he'd probably offer some crucial advice or perform a spell to help Harry.
Neville might be an unexpected supporter. He has grown a lot in courage and magical ability. He could offer his unique perspective on plants and Herbology - related magic. In a situation where Dumbledore least expects it, Neville's knowledge of magical plants could be the key factor. For example, Neville could use a plant's special properties to disrupt Dumbledore's magic or create a distraction that Harry can take advantage of.
Obviously, Harry would be the main character. There could also be his friends like Ron and Hermione. And perhaps some of his enemies like Draco Malfoy or other Slytherins.