In certain fanfictions, Dumbledore's secrets are the root of the perceived betrayal. For instance, his secrets about the Deathly Hallows. If Harry discovers that Dumbledore had known more about the Hallows all along and didn't share this knowledge, which could have changed Harry's journey and decisions, it could be written as a betrayal. Harry may feel that he was used and misled by Dumbledore, and thus the idea of betrayal emerges in these fan - created stories.
Another possibility is a miscommunication or false accusation within the fanfiction world. Someone could spread lies about Harry among the Weasleys, leading them to believe he has done something terrible and thus turning against him. But this is a far cry from the deep bond they share in the official 'Harry Potter' story.
In some fanfictions, Harry could be betrayed by friends due to jealousy. For example, if a friend is jealous of Harry's fame as the 'Chosen One'. Another reason might be a misunderstanding. Maybe Harry is wrongly suspected of using dark magic, and his friends, without proper investigation, turn against him.
In some fanfiction concepts, Harry might defeat an 'evil' Dumbledore if Dumbledore was secretly under the influence of a dark magic artifact. This could twist his good intentions and lead him to actions that Harry would oppose. Harry, with his strong sense of justice and loyalty, would then fight against this corrupted Dumbledore.
In some fanfiction, Harry might defeat Dumbledore if he discovers a powerful dark magic that Dumbledore is vulnerable to. For example, if there's a long - lost spell that can nullify Dumbledore's defenses. Another way could be that Harry is being controlled by a dark force that makes him turn on Dumbledore and, with its power, he overcomes him. However, this goes against the general nature of their relationship in the original series.
In some fanfictions, Hermione might betray Harry due to a misunderstanding. For example, if there were false rumors spread about Harry being involved in dark magic or having a secret, evil plan. Hermione, being a stickler for the rules and the greater good in the original series, might be misled into believing these rumors and thus betray Harry.
Well, Harry might outsmart Dumbledore by using his unique understanding of the magical world in ways Dumbledore doesn't expect. For example, Harry has a more direct experience with some dark magic items due to his encounters with Voldemort. He could use this knowledge to make decisions that seem counter - intuitive to Dumbledore but are actually more effective in a particular situation.
In some fanfictions, Dumbledore might be portrayed as betraying Harry by withholding crucial information. For example, if he knew more about Harry's fate or the true nature of the threats he faced but didn't share it all. This could make Harry feel betrayed as he was left in the dark and had to face greater danger without full knowledge.
Well, he could use it to uncover secrets that Dumbledore might have left behind. Since Dumbledore was a very knowledgeable and powerful wizard, his wand could hold the key to certain mysteries. Harry might be able to access hidden chambers or knowledge that was previously inaccessible. However, taking the wand could also bring a great deal of trouble. There could be those who would want to take the wand from Harry, thinking he doesn't deserve it or that it should be in their possession for their own dark purposes.
One possible reason could be that Harry breaks school rules in the fanfiction. For example, if he ventures into the Forbidden Forest without permission. Dumbledore is strict about the safety of students and such disobedience might lead to punishment.
Well, it could be that in these fanfictions, a dark influence overcomes Hermione and Ron. They might be manipulated by a powerful dark wizard who makes them believe that betraying Harry is the right thing to do. It could also be a miscommunication situation where they think they are helping but end up betraying Harry. For instance, they might be tricked into believing that Harry has turned bad and needs to be stopped.