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.
If Harry overhears Ron and Hermione fanfiction, it could lead to various reactions. Firstly, he might initially be shocked. He has always seen Ron and Hermione as his friends, and seeing their relationship fictionalized in a way he didn't expect could be jarring. Secondly, he could find it hard to look at Ron and Hermione in the same way for a while. He might keep thinking about the wild ideas in the fanfiction. And finally, he could end up teasing Ron and Hermione about it, which would surely make things interesting between them.
Perhaps Harry overhears a very private and heartfelt conversation between Ron and Hermione. He might realize that their relationship has deepened in a way he hadn't noticed before. This could make Harry feel a bit left out at first, but then he would probably be happy for them. He could also use this new knowledge to be more understanding of their actions and decisions in the future.
Harry might react with shock. If he overhears something unexpected like Ron and Hermione confessing their love for each other, it would be a big surprise. He might stand there frozen for a moment, not knowing how to process it.
Harry's reaction would depend on the nature of the fanfiction. If it's a cute, romantic fanfiction about Ron and Hermione, he might smile to himself and think it's kind of sweet. However, if it's something that distorts their characters or has a negative slant, he could get defensive. He might even try to find out who wrote it and why they would write such a thing about his friends.
Hermione might seek revenge. Given her intelligence and magical abilities, she could use her skills to get back at Harry and Ron for their betrayal. This could lead to a big rift in their friendship and even endanger their common goals in the wizarding world. She might also side with other characters who are against Harry and Ron, changing the whole dynamic of the story.
Well, it might also lead to a split in the wizarding community. Some might side with Ron and Hermione, believing they had a good reason to abandon Harry. Others would be outraged and try to find Harry and bring him back. This could create chaos and internal conflict within the wizarding world, making it vulnerable to outside threats as well.
One consequence could be that it creates a rift between Ron and Hermione. Hermione might be grateful to Lucius, which could make Ron jealous or angry. This could lead to a strain in their relationship, and they might have to work through their feelings about Lucius' interference.
Hermione might start to distance herself from Ron. She could avoid sitting next to him in class or at meals, and stop including him in her study groups or other activities.
Harry might be really angry with Ron and it could damage their friendship. They've been through a lot together, and stealing something as important as the cloak is a big betrayal.
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.