Well, immediately after the kidnapping, there would likely be chaos. The Romans would be up in arms, demanding Reyna's return. Meanwhile, Percy's friends at Camp Half - Blood might be shocked and confused. Some might support Percy if they think he has a good reason, while others would be against his actions.
In the end, the resolution could be that Percy releases Reyna unharmed. This could lead to a new understanding and alliance between the Greeks and Romans. They could work together more closely in the future to face the various threats in the world of the demigods. Or, there could be a big showdown between the two camps that Percy has to stop by making amends for his actions.
One idea could be that Percy is under a spell or some kind of mind control when he kidnaps Reyna. Maybe a new villain has emerged and is using Percy as a tool. In the fanfiction, Percy might be fighting against this internal force while Reyna is trying to figure out how to break the spell on him.
In the fanfiction, Percy might face new challenges related to his demigod status. Maybe he has to deal with the aftermath of the war, like rebuilding Camp Half - Blood or helping new demigods adjust.
One possible plot could be that Percy is being controlled by some dark force. Maybe a new evil god or an ancient curse. This force makes him kidnap Reyna because she has some important knowledge or power that the dark side wants. For example, she might know the location of a powerful weapon that could tip the balance in a coming war between the gods and the titans' remnants. Percy, against his will, takes Reyna to a secret location. Reyna, being a strong and resourceful character, tries to figure out a way to break Percy out of the control while also dealing with the situation at hand.
In fanfiction, the idea of Percy Jackson and Reyna being siblings is a concept that some writers like to play with. It can add an interesting twist to the story. Maybe they create a backstory where they are siblings separated at birth or something similar. But remember, this is just in the realm of fan - created stories and not part of the original mythology or the main series. Fanfiction gives fans the chance to explore relationships in new and unexpected ways.
The Aphrodite cabin might kidnap Percy with the intention of using his popularity or hero status. They could be planning to use his influence to promote Aphrodite's ideas of love and beauty. They might dress him up in fancy clothes, put him in situations where he has to charm others, all while he's trying to figure out a way to escape and get back to his normal life.
It could be an old enemy of the gods who has been biding their time. Maybe a powerful Titan that was thought to be defeated but has found a way to come back. This Titan could use Percy to kidnap Reyna because she has a connection to a certain power that the Titan wants to use to regain full strength and overthrow the gods once again.
In the 'Percy Jackson Disappears' fanfiction, perhaps Percy could be kidnapped by an unknown enemy. Maybe it's a new villain who has a vendetta against the demigods. This would lead to his friends, like Annabeth, going on a desperate search for him, facing many dangerous challenges along the way.
In fanfiction, Percy could be in the hospital because he was captured by an enemy and tortured. Now he's there being healed by the camp's healers or some advanced demigod medical technology. Another possibility is that he's having some sort of identity crisis related to his demigod status and it's causing him physical and mental stress, so he's in the hospital for both medical and psychological help.
Jason is another good choice. He has a history with both Percy and Reyna. His leadership skills and his connection to the Roman side of the demigod world could bring in new plotlines. For example, he could help Percy and Reyna understand some of the more complex Roman demigod politics that they need to navigate.
Well, in this fanfiction, Percy's immortality could lead to some really interesting character development. He may start to feel lonely as he realizes that he will outlive all of his friends. This could cause him to be more withdrawn at first. But then, as he interacts with the students at Westover Hall, he might find new meaning in his immortality. He could start to see it as a way to protect others not just for a short time, but for as long as he exists. He could also form deep and lasting friendships with those who accept him for who he is, regardless of his immortality.