Another possibility is that he discovers some dark secret about the superhero world or his own powers. This new knowledge could be so terrifying or disturbing that he chooses to run away to avoid dealing with it right away. He might need time alone to figure things out.
In some fanfictions, it could be that he has made a big mistake. For example, if his actions as Spider - Man led to the harm of an innocent person. He would be so guilt - ridden that he decides to run away from everything, including his friends and family in Queens.
She could run away because of a broken heart. Maybe she had a relationship that ended badly, and she needs to get away from the memories. In the process of running away, she could meet new people who help her heal and grow as a person. This type of storyline often explores the more vulnerable side of fem Tsuna.
One possible reason could be that he feels misunderstood by his family or friends. Maybe he has some secrets that he's afraid to share, and the fear of being judged makes him run away.
Maybe Pikachu is feeling neglected by its trainer. If the trainer has been paying more attention to other Pokemon or is too busy with something else, Pikachu might decide to run away to get some attention.
In some fanfiction scenarios, Peter might be dealing with some sort of internal power struggle. If his spider - powers are evolving or being affected in some way, it could lead to his collapse at school. For instance, if there's a glitch in his powers that causes his body to have sudden energy drains or physical reactions, like collapsing, while he's at school trying to act normal.
One possible reason could be extreme stress. Peter Parker has a lot on his plate, being Spider - Man and having a normal life. If in the fanfiction he faces a series of really tough situations like failing to save someone important or being hunted by a very powerful enemy, the stress might get to him and lead to self - harm as a way of coping. Another reason could be feelings of isolation. Even though he has friends, he might feel like no one truly understands the dual life he leads, so in the fanfiction this could drive him to such a desperate act.
One reason could be a fight with a powerful enemy. Maybe a new super - villain has emerged in the city and Peter underestimated their strength during the battle in the alley.
Well, one reason could be that he's on a secret mission for S.H.I.E.L.D. that requires him to go undercover and cut off all contact. Maybe he's investigating a new super - villain threat that's too dangerous to let anyone know about.
His double life is also a big factor. Constantly having to balance being Peter Parker, a normal student, and Spider - Man, a superhero with great responsibilities, can be extremely taxing. He might feel like he can't be fully himself in either role, which can cause a sense of isolation and ultimately depression. In fanfiction, this can be shown through his inner monologues and his interactions with others.
One reason could be that she has big dreams that can't be fulfilled where she is. Another might be that she's running from a person who's threatening her. Maybe she just wants to explore the world and find herself.
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.