Dumbledore might give Harry advanced spellcasting training. He could teach Harry some of the more complex and ancient spells that are not commonly taught at Hogwarts.
It might make Harry more confident. With Dumbledore's training, Harry gains more knowledge and skills, which gives him the confidence to face challenges.
The relationship between Harry and Dumbledore in this fanfiction can be really fascinating. Dumbledore is a very powerful and wise wizard, and his training of Harry might involve not only magic but also life lessons. They could have some deep conversations that shape Harry's view of the wizarding world and his role in it.
In such a fanfiction, perhaps a major plot point is how Dumbledore trains Harry to face a new and greater threat. It could be a dark wizard more powerful than Voldemort, and Harry has to learn a whole new set of strategies and magic under Dumbledore's guidance. Harry might also develop a deeper understanding of the wizarding world's history and secrets through Dumbledore's teachings, which could be a key part of the plot.
Dumbledore, as Harry's guardian in the fanfiction, would probably use his influence in the wizarding world. He could make sure that Harry is taught by the best teachers at Hogwarts. He'd also be there to offer advice and guidance, especially when Harry faces challenges like dealing with Voldemort or other dark forces. For example, he might teach Harry some advanced defensive magic privately to better protect himself.
Well, in some fanfictions, Harry might attack Dumbledore if he discovers that Dumbledore has been using him as a pawn in a bigger game all along. This feeling of betrayal could drive him to lash out. Also, if there is a prophecy that he misinterprets to mean Dumbledore is a threat to his future or the future of his friends, that could be a motive.
Snape can be a prominent character. Given his complex relationship with Dumbledore and Harry, his perspective could add a lot to the story. He might have some insights into Dumbledore's actions that Harry doesn't know about, and his reactions to Harry's blaming could vary from being scornful to having a moment of understanding. Luna Lovegood could also be a part of it. Her unique view of the world might make her offer some different viewpoints on the situation between Harry and Dumbledore.
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.
Perhaps there are safety concerns for the students that Dumbledore is not addressing adequately. Harry, having a strong sense of responsibility for his fellow students, may feel that the only way to ensure their safety is to remove Dumbledore from his position. He might believe that Dumbledore's actions or inactions are putting the students at risk, and thus he takes matters into his own hands.
The relationship would become very strained. Harry's rejection would likely make Dumbledore re - evaluate his actions and how he has interacted with Harry. Dumbledore might be shocked at first, since he probably thought Harry was on the same page as him most of the time.