One interesting concept could be the crossover of the Percy Jackson world with the 'Olympus has fallen' scenario. Maybe the demigods have to deal with a political takeover of Olympus in a more modern, thriller - type situation, like in 'Olympus has fallen'.
In 'Percy Jackson Olympus has fallen fanfiction', an interesting concept could be the moral dilemmas the characters face. When Olympus has fallen, the normal order is disrupted. The demigods might have to decide whether to follow the old rules or create new ones. Some might be tempted to take advantage of the chaos for their own gain, while others will strive to restore the former glory of Olympus. This exploration of character integrity and decision - making in a chaotic situation can add a lot of depth to the fanfiction.
Another possibility is a new, unknown force from the Underworld. Maybe Hades has lost control over some dark entity that has grown in power and now aims to take over Olympus. This entity could be extremely powerful, with abilities that the demigods have never faced before. It would be a great antagonist as it would force the Percy Jackson characters to adapt and find new ways to fight in order to save Olympus.
Well, time - travel is a cool concept in percy jackson fanfiction. Imagine Percy going back in time to change some crucial events in the history of the demigods. Also, there are fanfictions that focus on Percy having new powers or abilities. This could be because of some new magical artifact or a special training he undergoes. And of course, the idea of Percy having to adapt to a completely different camp, like a Roman - Greek hybrid camp, is really engaging.
A great fanfiction idea is to have the heroes of Olympus time - travel. They could go back to the time of the ancient Greek heroes and interact with them. Maybe Percy meets Theseus and they have to compete in some sort of challenge. Or the story could focus on a character like Nico di Angelo and his journey to discover more about his powers in a place that is off - limits to most demigods, like the Underworld's deepest secrets. There could also be a fanfic where the demigods have to deal with a curse that affects their powers in strange ways.
One possible plotline could be Percy being betrayed by the gods and thus deciding to take on Olympus. Maybe he discovers some dark secrets about the gods' rule that make him believe destruction is the only way to bring true justice.
Maybe there's a plot where the demigods are trying to improve the living conditions on Olympus. Since it's a place full of powerful beings, it might be in a bit of chaos. So they could be working on things like building better homes or creating a more organized system for the lesser - known gods.
One idea could be Percy having to face a new, unknown monster that is immune to water. He'd have to rely on his other skills and the help of his friends in a completely different way.
In some 'Percy Jackson Raised on Olympus' fanfictions, there could be a plotline about Percy uncovering long - hidden secrets of Olympus. For example, he might discover a forgotten prophecy that has implications for the entire pantheon. Also, his interactions with the nymphs and other mythical creatures in the Olympian realm can make for an exciting story. Maybe he has to protect them from a new threat that is emerging within the boundaries of Olympus itself.
One interesting concept could be a darker version of Percy's powers. For example, instead of just controlling water, he might be able to use it in more menacing ways, like creating water blades that can cut through almost anything. Another concept could be a darker side to his relationships. Maybe his friendship with Grover takes a turn, and there's more conflict and distrust. Also, a darker Percy might have a different view on the gods, perhaps feeling more resentful towards them for all the hardships he has faced, instead of just being the hero who blindly follows their orders.
One interesting concept could be the modernization of the Percy Jackson world in a gaming context. For example, how the demigod powers are translated into gaming abilities like special moves or skills. Another could be the creation of new quests within the game that are inspired by the original books, such as finding lost artifacts from Greek mythology in a virtual world.
A cool concept might be a modern - day mortal who somehow drops into the world of Percy Jackson. Maybe they have some hidden knowledge or ability that helps them survive and make an impact. They could introduce new technology or ideas from the real world that the demigods have never thought about, like advanced medical knowledge or new forms of communication.