Another idea is a time - travel fanfic. Phoebe somehow travels back in time and meets a younger Percy. She knows about his future and tries to help him avoid some of the hardships he'll face, but in doing so, she risks changing the future in unforeseen ways.
One idea could be a story where Percy and Phoebe team up to face a new threat that neither of them could handle alone. Maybe it's a powerful monster that has the ability to control water and fire, so Percy's water powers and Phoebe's skills need to be combined.
A fanfic could explore a scenario where Phoebe gets transported into Percy's world. She has to quickly adapt to the demigod life, and Percy has to show her the ropes. They could form a close bond as they train together and face challenges in Camp Half - Blood.
Well, obviously Percy Jackson and Phoebe are the main characters. Percy is a demigod with the power over water, son of Poseidon. Phoebe is another character, who might have her own unique set of skills depending on how the fanfic author writes her.
One great Percy Jackson and Phoebe Lemon fanfiction could be one where they team up to solve a mystery in the demigod world. Maybe they have to find a lost artifact that has the power to disrupt the balance between the gods and mortals.
Well, you could have a fanfic where Percy is given a science homework about marine biology, and he uses his knowledge from being the son of Poseidon to write an amazing paper. He might even bring in some sea creatures from the ocean to show as examples, which of course causes chaos in the classroom. Another idea is that the whole demigod gang has to do a group project on mythology, and they each contribute their own unique experiences with the gods and monsters.
In a 'Percy Jackson tattoo fanfic', you could explore the idea of a tattoo artist who is actually a minor god or goddess. The story could follow Percy or another character as they go to get a tattoo from this divine artist. The tattoo could have powers that are both a blessing and a curse, like it gives the wearer enhanced strength but also attracts more monsters. And the process of getting the tattoo could be filled with mythological elements, like the ink being made from the essence of a magical creature.
One idea could be a fanfic where Percy has a dream that he's in an alternate version of Camp Half - Blood. In this dream, the cabins are arranged differently, and there are new campers with strange powers. Another idea is a dream where Percy dreams of his future, seeing himself as a teacher at Camp Half - Blood, passing on his knowledge and skills to the new generation of demigods. Or perhaps a fanfic where Percy has a recurring dream about an ancient prophecy that he has to figure out in his waking life.
Another concept could be a Phoenix being reborn as a human - like form and becoming Percy's ally. They team up to fight against a new threat that neither could face alone. The Phoenix - human hybrid could have special powers that combine the best of both worlds, and their friendship could be a central theme in the fanfic.
One interesting plot could be Phoebe joining Percy on a quest. Maybe she has some unique powers that help them overcome the challenges they face, like being able to communicate with certain mythical creatures that Percy can't. This could add a new dynamic to the typical Percy Jackson quest.
One idea could be that your inserted character is a new camper who has a special ability related to an ancient and forgotten Greek magic. This character then helps Percy and his friends in a battle against a revived mythological villain that is more powerful than any they've faced before.
You could write a fanfic about Percy and Annabeth in the future, like when they are adults. They could be building a new Camp Half - Blood type of place for demigods all over the world. But there are those who oppose their ideas, and they have to deal with politics and power struggles, all while maintaining their relationship strong through it all.
A good crossover idea is that there's a spell gone wrong in the wizarding world that starts to affect the boundaries between the mortal world and the world of the Greek gods. Hermione, being the brilliant witch she is, tries to figure out a solution, and Percy, with his knowledge of the Greek world, gets involved. They could travel through different dimensions together, facing challenges from both magical creatures and mythical beasts.