One reason could be a misunderstanding. Maybe Hermione does something that Harry misinterprets, like getting too involved with her studies and seeming to neglect their friendship. Another could be outside influence. For example, if there are other characters who spread false rumors about Hermione to Harry, it might drive a wedge between them. Or perhaps Harry starts to develop different values and beliefs that clash with Hermione's, leading to a breakdown in their friendship.
It could be because of a personal growth arc for Harry. He might decide he needs to be more independent and break away from his old friendships. Hermione, being very intelligent and often having her own strong opinions, could be seen as a bit overbearing by Harry at this point in his growth. So, he chooses to stop being friends with her to find his own path.
The story could develop with Hermione trying to figure out what went wrong. She might start investigating, talking to other friends they have in common to see if they know anything. Meanwhile, Harry could start making new friends who are more in line with his new mindset. But he might start to realize that he misses Hermione's unique qualities.
One possible reason could be a misunderstanding. Maybe Hermione does something that Harry misinterprets, like siding with someone he doesn't trust in a Hogwarts issue. Another reason might be jealousy. If Hermione starts getting closer to another character, Harry could feel left out and stop talking to her. Or perhaps a dark influence affects Harry's mind, making him think Hermione is a threat to him in some way.
Perhaps the writer of the fanfiction is trying to create a different character arc for Harry. Maybe he has faced so many hardships that he becomes disillusioned. For example, if he has lost too many loved ones and feels that his efforts are in vain, he might stop trying. It's a way to add a new layer of depth to his character.
One reason could be his status as the Boy Who Lived. In the original story, Harry has this special aura about him, and in fanfiction, Hermione might be drawn to that in an obsessive way. Also, his bravery and leadership qualities could be factors that make Hermione overly interested in him.
One possible reason could be that he has been through so much in his original adventures that he's just tired. He might feel like he's constantly being put in new, often contrived, situations in the fanfiction and he simply wants to step away from all the chaos and drama.
Well, one reason could be jealousy. Maybe his friends envy his fame or special abilities. Another could be misinformation. If they are fed false information about Harry, they might turn against him. For example, if someone convinces them that Harry is secretly working for the enemy.
One reason could be that Ash has achieved all his major goals as a Pokémon trainer. He might have won all the important championships and feels there's nothing more to prove in that area. Another reason could be that he has had some kind of traumatic experience related to Pokémon training, like losing a very dear Pokémon in a battle that makes him not want to continue. Maybe he has also found a new passion, such as Pokémon research. He could have met some inspiring Pokémon researchers and decided to shift his focus from training Pokémon to studying them.
One possible reason could be a misunderstanding. Maybe there was a miscommunication between Hermione and her friends, which led to them leaving her in the fanfiction. For example, if Hermione made a decision without consulting them, they might feel left out and decide to leave.
One possible reason could be that the fanfiction author wants to focus on other characters. Maybe they feel they've explored Naruto's character enough and want to give more spotlight to characters like Sasuke or Sakura. Another reason might be that the plot of the fanfiction takes a turn where Naruto's acting skills are no longer relevant or needed.
Maybe he is attracted to Hermione's character traits like her intelligence and courage. Fanfictions often explore different aspects of her personality in unique ways that might intrigue him.