His relationship with Annabeth would also be affected. If he travels back far enough, he might meet a younger Annabeth. This could create a whole new dynamic, as he already knows her future self. He would have to be careful not to change things too much, but at the same time, he could form a different kind of bond with her in the past.
His relationship with his father Poseidon would be different. He might see a side of Poseidon that he never knew before, like when Poseidon was younger and less experienced. This could change how Percy views his father and their connection.
With his friends, if he goes back in time before he met them, he could be the one to influence their lives in a different way. For instance, he could be the reason a friend made a certain decision that changed their life path, which would be a strange role reversal.
If Merlin travels back in time, his relationship with Arthur would be very different. In the past, Arthur might not trust him at all at first. Merlin would have to prove himself all over again. With Gwen, he might be more aware of her future importance and try to protect her in a different way. And his relationship with the other knights could be completely new, as they might see him as a stranger with strange powers.
If Ianto travels back in time, his relationships with the Torchwood team in his original time would be put on hold. They would be left wondering where he went. In the past, he might form new relationships. For example, he could become friends with an ancestor of one of his present - day colleagues. This would create a strange connection between the past and the present for the team when he eventually returns.
In a Percy Jackson vampire fanfiction, his relationships would be transformed. His friends at Camp Half - Blood would likely be very wary of him. They've fought against monsters, and now Percy is something that was once considered a monster. His relationship with his mother would be difficult. She'd have to accept that her son is now a vampire. And with Annabeth, it would be a complex situation. Their love would be tested as she tries to understand and accept this new version of Percy.
His relationship with Annabeth would be very different. Instead of their usual dynamic on land, they'd have to figure out how to interact in the water. Annabeth might have to learn to trust Percy in his new form, and Percy would have to deal with any insecurities about his merman self. Their relationship could become more strained as they adjust, or it could grow stronger as they face new challenges together.
If Percy became the God of Destruction in the fanfiction, his relationships would become very complex. With his enemies, they would be even more terrified of him. However, some of his former enemies might also try to ally with him, seeing his power as a means to their own ends. His relationship with his mother would also change. She would be worried about her son, but also proud of his new - found status in a way. Percy would have to navigate these new relationship dynamics carefully.
His relationship with Annabeth would become more complex. Annabeth might be worried about Percy's new power getting out of control. She would try to help him find a balance, which could lead to some arguments but also deeper understanding.
His relationship with Annabeth would be different. She might have to get used to Percy being a pegasus. There could be some initial awkwardness, but also a deeper understanding as she sees him in a new form.
With his friends like Grover, Percy would seem like a completely different person. Grover is used to Percy's emotions guiding his actions. Now, Percy would be cold and calculating. His friends would have to constantly remind themselves that this is still Percy, but it would be hard for them to connect on the same level. They might start to doubt if they can still trust him, as his lack of emotions could make his decisions seem unpredictable.
If Natsu goes back in time, his relationships would be very different. With his friends, he might have a new level of understanding. For example, he could see how they grew up and the challenges they faced in the past. He might be more protective of them, especially if he knows what's going to happen in the future. His relationship with Lucy could also change. He could see her in a new light, perhaps realizing things about her that he didn't before when he first met her in the present.
If Percy Jackson was a vigilante superhero in a fanfic, his relationships would be in flux. His relationship with his mother would become more strained as she would be worried about his safety. His friendships with other demigods would be tested. Some, like Grover, might try to persuade him to stop because it's too dangerous. However, Percy's new role could also attract new allies. There could be other half - bloods or even mortals who share his sense of justice and would be drawn to him, changing the dynamic of his relationships in unexpected ways.