If the fanfiction was written by someone they really trusted, like Dumbledore (if he were still alive and into writing fanfiction, which is a wild thought). Since they respected his wisdom, they might be more inclined to believe it.
Well, it could be really awkward for him. He might feel a bit strange knowing that people are writing fictional stories about his two best friends. He could also be a bit protective and might not like the way some fanfictions portray Ron and Hermione. Maybe he'll be amused too, depending on the content of the fanfiction.
It could be that Ron and Hermione abandon Harry due to a prophecy that they misinterpret. They believe that by being with Harry, they will bring doom to the wizarding world. So they go into hiding. Harry, on the other hand, is determined to change the course of the prophecy. He embarks on a journey to find the truth behind it, all while feeling the pain of his friends' desertion. He has to fight against dark forces that are taking advantage of the situation.
In such a fanfiction, it might be that Harry and Ron are influenced by a powerful dark spell. This spell makes them see Hermione as a threat, so they abandon her. Hermione then has to find a way to break the spell's influence on them while also dealing with the loneliness and danger she's now in. She could seek help from other Hogwarts students or even some friendly magical creatures.
A common plot point is when Harry and Hermione share secrets that Ron doesn't know. For instance, they might be researching a powerful spell in the library and keep it from Ron, making him think they are excluding him on purpose.
Yes, there are likely such fanfictions. In some, the initial bullying could be due to a misunderstanding. Maybe they were influenced by some dark magic or false rumors that made them act mean towards Hermione. Eventually, they realize their mistake and make amends, perhaps by going on a dangerous adventure together where they see Hermione's true value and loyalty.
If Ron and Hermione leave Harry in the fanfiction, it would change the entire fabric of the story. Harry would have to reevaluate his relationships with other characters. For example, he might turn to Neville for support more often. Also, the power dynamic within the wizarding world could shift. Since Ron and Hermione were important figures in the fight against Voldemort, their absence could give the Death Eaters an advantage, or it could inspire others to step up in unexpected ways. Harry would be forced to grow in ways he hadn't before, and it would be a journey full of self - discovery and new challenges.
It could be due to a misunderstanding. Suppose Ron overhears a conversation between Harry and Hermione that he misinterprets completely. He might think they are plotting against him or don't really consider him a true friend. So in a fit of anger and hurt, he decides to betray them.
Maybe they run away because they are tired of the constant danger at Hogwarts. They've faced so many threats, and they just want a break. So they run to a peaceful place where no one knows them.
A possible plot could be that the Muggle teacher is being targeted by a dark wizard who wants to use the teacher's knowledge of Muggle technology for evil purposes. Hermione, Ron, and Harry find out and decide to protect the teacher. They have to hide the teacher in the wizarding world and teach them basic self - defense spells.
One possible plot is that a magical object affects Harry and Ron's minds, making them bully Hermione. Hermione, at first, is heartbroken. But she then uses her intelligence to find a way to reverse the object's effect. Meanwhile, she also stands up to them, showing her strength. When the boys are back to normal, they are ashamed of their actions and have to make amends. This could also lead to a deeper exploration of the importance of true friendship and not being easily influenced by external factors.