Another possibility is that his time - traveling could create some sort of time paradox. This might lead to all sorts of strange and unexpected consequences. His presence in the past could disrupt the normal flow of magic and time, and he'd have to find a way to fix it before everything goes wrong.
In such a fanfiction, Percy might use his knowledge of the future to change some key events in the past. For example, he could prevent some of the earlier disasters or conflicts in the Percy Jackson universe. Maybe he'd try to stop the first encounter with a certain monster in a different way to avoid the chaos it caused.
Well, he could try to change all the tragic events that occurred in the original timeline. Maybe he'd prevent certain deaths or make different alliances. For example, he might approach Suzaku earlier and try to convince him of his true motives, thus avoiding their later conflicts.
Perhaps Percy will discover secrets about his family or his powers that were previously unknown. Since he's in the past, there could be ancient magic or knowledge that he stumbles upon. This newfound knowledge could give him an edge when he returns to his own time, if he ever does. He might also face challenges like trying to blend in with the people of the past, as his modern ways could make him stand out and cause suspicion.
Well, he could prevent some of the great disasters that happened in his world. Maybe he could stop the Fire Nation's initial attacks and change the whole course of the war. He might also be able to save some important characters who died in the original timeline.
In this situation, Naruto could also use his ninja skills in a discreet way. For example, he could use his shadow clone jutsu to gather information without being noticed. He might discover that the ones who framed him are actually part of a larger conspiracy against the Hidden Leaf Village. So, his main goal would then not only be to get out of prison but also to expose this conspiracy.
Well, in this type of fanfiction, Naruto could change the relationships he had at the academy. He may befriend Sasuke earlier and in a different way, perhaps preventing Sasuke from being so cold towards him initially. Also, he could have more time to train with his classmates and help them improve too, which would make for a very different dynamic in the group.
Well, he might find a world where magic has been completely integrated with Muggle technology. For example, broomsticks are now used for inter - planetary travel and there are magical apps on smartphones. Also, Hogwarts could be a much larger and more diverse place, with students from all over the universe coming to study.
His character would likely become more mature. Seeing the past and knowing the future would make him more responsible. He might not be as reckless as he was before.
In fanfiction, the possibilities are endless. It could be that they go on an adventure to a previously unknown magical land or face a powerful dark wizard who was thought to be defeated.
Well, it could go in many directions. They might travel to a previously unknown magical realm or encounter creatures that were only hinted at in the original series.