It could also be due to external pressure. The media or some powerful figures in the fanfiction world might force Tony to stay away from Peter. They could spread false rumors about their relationship or use their influence to separate them for their own gain.
Perhaps Kakashi feels that Naruto is becoming too reliant on him and not developing his own skills independently. So, in order to force Naruto to become stronger on his own, he decides to abandon him. This is a tough - love approach. Naruto has great potential, but he needs to learn to stand on his own two feet, and Kakashi may think this is the best way to make that happen.
One possible reason could be that Sakura realizes she has different goals or values that are not compatible with being around Naruto. Maybe she discovers a new path in life that doesn't involve him, such as focusing on her own medical ninja career without Naruto's chaotic lifestyle interfering.
Another reason might be related to Pikachu's own growth. As Pikachu becomes more powerful and self - aware, it might feel that it needs to go on its own journey without Ash. It could be seeking new challenges and experiences that it believes Ash can't provide, like exploring regions that Ash has no intention of going to or training with Pokémon of a different caliber.
One possible reason could be that Tony Stark is being overly critical of Peter's superhero work. Maybe Peter made a big mistake during a mission, and Tony's harsh words in his attempt to correct Peter made him cry. For example, if Peter accidentally put civilians in danger and Tony scolded him severely.
Maybe Tony believes that Peter is in some kind of danger that May can't protect him from. So, he takes Peter away to keep him safe in a more secure and technologically advanced place that he can provide.
In some fanfictions, Naruto might abandon his family due to a false prophecy that convinces him he's a danger to them. He may think that by leaving, he can protect them from harm that might come his way because of his past or enemies.
One possible reason could be jealousy. Maybe Peter has some natural talent or ability that Tony wishes he had, and this makes him mean. For example, if Peter is really good at something like coming up with innovative ideas quickly, and Tony, who is used to being the smartest in the room, feels threatened.
Maybe Peter has some urgent news to share. For example, he might have discovered a new threat to the city or a problem related to one of their projects. He could also be in trouble himself and needs Tony's immediate help.
Maybe Peter discovers that Tony has been keeping secrets from him that directly affect his life or safety. For example, if Tony has been secretly monitoring Peter without his knowledge, Peter might feel betrayed and cut ties.
One possible reason could be that Tony sees a lot of potential in Peter. In the original story, Peter has great powers and a good heart. The fanfiction might explore different scenarios of their relationship, like a mentor - mentee relationship in more depth. Tony might be interested in how fans envision their interactions and the growth of Peter under his influence.