A possible plot could involve a character going back in time to the beginning of the universe. This character, perhaps a demigod with special powers, witnesses the formation of the cosmos. They see how the different elements of the Percy Jackson world, like the Underworld, Mount Olympus, and the various magical creatures, came into existence. It could also explore how the concept of demigods was first conceived during these early times.
Maybe one of the primordial deities, like Gaea, could be the main character. The fanfic could explore her thoughts and actions as she was one of the first beings. It could show how her relationship with other primordial deities influenced the future of the universe, and how her actions in the beginning set the path for events that would unfold much later in the Percy Jackson series.
The morale among the demigods would be greatly affected. The Hunt is often seen as a symbol of strength and unity for female demigods. If Percy kills them, it might create a divide between male and female demigods, leading to internal conflicts within the demigod community. Also, it would change the way demigods view Percy. Some might see him as a hero for eliminating a potential threat, while others would see him as a murderer for killing the Hunt.
Well, if Percy stays as praetor, it could lead to a more stable leadership in Camp Jupiter. This might mean stronger defenses against external threats like the giants or other monsters. It also could change the power dynamics between the demigods of the two camps, as Percy has strong ties to Camp Half - Blood too. His continued presence as praetor might encourage more cooperation between the camps, which would be a big shift from the usual somewhat tense relationship.
One possible plot could be Percy Jackson using his powers to create new realms within the universe. He might face challenges from ancient gods who feel threatened by his new - found ability to shape the cosmos.
In a fanfic, perhaps Percy and his friends accidentally stumble upon Medusa's lair while on a quest. But instead of immediately attacking, Medusa offers them a deal. She says she will give them a valuable clue to complete their quest if they help her get revenge on one of the minor gods who wronged her in the past. Percy and his friends then have to decide whether to trust Medusa or not.
She could be a creation of a powerful witch who has a vendetta against the demigods. The witch uses dark magic to create the succubus and sends her to the Percy Jackson world. The succubus then uses her charm and powers to get close to Percy, either to steal his powers or to use him to get to the other demigods at Camp Half - Blood.
One interesting concept could be a world where the gods have lost their powers and the demigods have to find a new way to survive. Another might be an alternate universe where the camps, like Camp Half - Blood and Camp Jupiter, are merged from the start. And perhaps a universe where the monsters are the ones in control and the demigods are the hunted.
Well, in many Percy Jackson alternate universe fanfic, Leo Valdez is quite popular. People love to write about his inventions in different scenarios. Maybe he creates a super - powerful weapon that changes the balance of power between the demigods and the monsters. Grover also has his fans in these fics. He could be in a universe where he's the most powerful satyr ever and has to use his nature - related powers to save the world. And of course, Clarisse La Rue can be really interesting in alternate universes, like a Clarisse who teams up with her former enemies to fight a greater threat.
In many fanfics, Lucifer's presence can create moral dilemmas for the characters. Percy, who is used to a world of somewhat clear - cut good and evil (in terms of Greek mythology), now has to deal with Lucifer's more nuanced nature. This can lead to interesting internal struggles for Percy as he decides whether to trust or oppose Lucifer.
Another plot idea could be that Percy discovers a hidden underwater civilization that is not related to Poseidon. This civilization has its own set of rules and powers. Percy has to navigate through their complex society and politics while also trying to convince them to help the demigods in a coming war against an ancient evil that is rising again. The underwater civilization could have unique magic and technology that the demigods have never seen before.