One interesting plot could be Percy being a secret prince at the royalty school. He has to hide his demigod powers while also dealing with the politics and rivalries among the royal students. Maybe there's a mystery about his true heritage that is slowly uncovered throughout the story.
In some fanfiction, the plot could center around a prophecy related to the royalty school. Percy is seen as the key to fulfilling it. The school is filled with various magical and powerful beings, not just humans. Percy has to form alliances with some of them, while also being cautious of those who might be working against the prophecy. He discovers new aspects of his powers and himself during this journey at the royalty school.
Well, a plot might involve Percy and his friends from the normal Percy Jackson world being transferred to a royalty school. They have to adapt to the strict rules and etiquettes. There could be a competition at the school where Percy's unique skills, influenced by his demigod nature, give him an edge, but also make him a target for those who envy his abilities.
Percy himself is obviously very popular. His charm and his abilities as a demigod make him a central figure. Annabeth is also often included. Her intelligence and strategic thinking can play a great role in the royalty school setting. Another popular character could be Nico. His dark and mysterious nature adds an interesting element to the story.
In some fanfiction, a great plot is Percy getting involved in a high school mystery that turns out to be related to his demigod world. Like strange disappearances in the school are actually the work of a minor god who's using the students as sacrifices. Or perhaps Percy has to compete in a high school athletic event where his demigod powers give him an edge, but he has to be careful not to expose himself.
Another plot could involve a high - school - themed quest. For example, there's a hidden artifact in the school that has some powerful mythological significance. Percy and Annabeth compete in a school project that unknowingly leads them to discover the existence of this artifact. Along the way, they face rival students who are also unknowingly being influenced by minor gods to get to the artifact first.
A plot might involve Percy and his friends competing in a school - wide fitness tournament. But there's a twist - some of the events are magically rigged. Percy has to use his wits and his powers to overcome the magic and win fairly. This could also be a great opportunity for character development, as the friends learn about teamwork and perseverance through fitness challenges.
One interesting Percy Jackson royalty fanfiction could be where Percy discovers he is heir to a long - lost underwater royal kingdom. In this fanfic, he has to learn the ways of the court and deal with political intrigue among the mer - people. Another might involve Annabeth being revealed as a descendant of an ancient Greek royal line and having to reclaim her throne in modern times while still dealing with the usual monsters and quests. There could also be a fanfic where the entire Camp Half - Blood is thrust into a world of royalty when they find out that their demigod powers are linked to an ancient royal bloodline that they must protect.
One interesting plot could be Percy having to face an alternate version of himself that has turned evil due to some dark magic. This would create a great internal conflict as he battles not only an external foe but also his own dark side.
One interesting plot could be Percy and his friends going on a quest in a new, unknown realm. Maybe a place that's not part of the regular Greek mythology but still related in some way.
Another plot might be a scenario where Percy tries to reason with Kronos. He could attempt to understand Kronos' motives for wanting to destroy the Olympians and find a compromise. This would be a complex and emotional journey as Percy has to face the being who nearly destroyed his world.
One interesting plot could be where the NPU (assuming it's some new power or entity in the Percy Jackson universe) is a key to unlocking an ancient prophecy that no one knew existed. Percy and his friends have to figure out how to use the NPU to their advantage while also dealing with the usual monsters and gods trying to stop them.
A cool plot could be a time - travel fanfiction. The Minotaur travels back in time to the era when the gods were more actively involved in the mortal world. He could interact with the gods, and Percy has to follow him through time to stop him from causing chaos. This would involve Percy having to deal with different rules and powers in the past, and also understanding the Minotaur's motives for going back in time.