It could be a very strained relationship. Harry would likely be extremely hurt and angry, and Hermione would be filled with guilt. There might be a lot of cold stares and avoidance at first. Harry might not be able to trust her again easily, if at all.
The relationship could start with Harry feeling a deep sense of betrayal. He might cut off all communication with Hermione. However, as the story progresses, Hermione could try to make amends. She could start by helping Harry secretly, without him knowing at first. This could slowly lead to a tentative reconciliation, but the trust would always be a bit broken.
In the world of fanfiction, this could be a very dark and interesting plot. It might be that Ron is influenced by some dark magic or some external force that makes him turn against his best friends. Maybe he's jealous of Harry's fame or feels overshadowed by Hermione's intelligence, leading to his betrayal.
Another possibility is that in the fanfiction world, Hermione could be influenced by external forces. For instance, a powerful dark magic or a mind - controlling spell might make her act against Harry. It could also be that she is pressured by other characters, like the Ministry of Magic or some pure - blood supremacist group, to betray Harry for what they think is the 'greater good', which she wrongly believes in and ends up losing Harry's trust.
Often, fanfic writers will put Harry and Hermione in situations where they are directly in the path of the Ringwraiths. This can lead to some really intense and exciting scenes. The Ringwraiths, with their dark and menacing presence, can be used to create a lot of suspense. Harry and Hermione's characters may be developed further as they deal with the fear and danger that the Ringwraiths bring.
Often, it ends with Hermione realizing her mistake. She might fight to make amends and try to save Harry from whatever danger she has put him in. For example, if she had handed him over to the bad guys, she could then turn against them and help Harry escape.
It depends on the specific plot of the fanfiction. It could be a friend who turns against her due to jealousy, or perhaps a false ally within the so - called 'light' side who has ulterior motives.
Often, Parseltongue is portrayed as a powerful and somewhat dangerous ability. In fanfiction about Harry and Hermione, it might be used as a tool to overcome obstacles. For instance, if they encounter a locked chamber that can only be opened with Parseltongue commands.
Hermione's possessiveness can also be shown by her getting angry when Harry doesn't consult her first. For instance, if Harry makes a decision about a mission without talking to Hermione in the fanfiction, she'll be furious. She believes she has a right to be in the know and have a say in Harry's life because of their deep friendship (or in some cases, a hinted romantic relationship), which is a clear sign of her possessiveness.
Often, Harry and Hermione have to fend for themselves without Ron at first. They might feel betrayed and angry, but they also realize they need to be stronger. Then, they start to uncover the real reasons behind Ron's betrayal. Maybe they find out that Ron was being controlled or manipulated, and they try to save him from the dark side he has fallen into.
In many fanfictions with such a plot, it could be a so - called friend who betrays Hermione perhaps out of jealousy. Maybe they are envious of Hermione's intelligence and popularity at Hogwarts, and for some self - serving reasons, they choose to betray her.
It's popular because Hermione is a well - loved character. Seeing her in a situation where she's betrayed by everyone adds a lot of drama. It's a way to explore her character in a different light, showing her vulnerability and her ability to persevere.