Well, one possible scenario in such a fanfic could be that Harry Potter is jealous of Percy Jackson's connection to the sea. Since Harry has his own element of water in the form of the Black Lake at Hogwarts, but Percy has this vast and powerful connection to all of the oceans. It could create a really interesting dynamic where Harry feels overshadowed in a way.
A simple way would be through their powers. Harry sees Percy's instant and powerful control over water, while his own magic related to water is much more limited. This makes him envious.
One great fanfic could be 'Jealousy in Hogwarts Halls'. In it, Harry's jealousy of Percy might stem from Percy's academic achievements and the way he's always so well - regarded by the teachers. It shows how Harry, who already has so much on his plate, struggles with this new emotion. It's a really interesting take on the characters and their relationships within Hogwarts.
One possible fanfic could be where Harry Potter, in a time of great need in the wizarding world, unknowingly summons Percy Jackson. Percy arrives, confused but ready for an adventure. He might bring his unique demigod powers like controlling water and his sword fighting skills to help Harry against dark wizards. The two could have an initial clash of cultures, with Percy being used to the Greek mythology world and Harry to the wizarding world.
Well, it could be really exciting. They could combine their magical powers. Percy with his water - controlling abilities and Harry with his wizardry. Maybe they'd fight together against common enemies, like some dark forces that threaten both the wizarding world and the world of Greek gods. They could also learn from each other's cultures. Percy could show Harry the wonders of the Greek pantheon and Harry could introduce Percy to the magic of Hogwarts.
One popular fanfic idea could be Percy being summoned to a modern-day high school. In this fanfic, he might be summoned by a group of students who accidentally stumble upon an ancient spell. Percy then has to deal with the normal high school problems like bullies and exams, all while trying to keep his demigod identity a secret.
One idea could be that they discover their family connection during a magical crisis. Maybe a dark force is threatening both the wizarding world and the world of the Greek gods, and their combined powers as cousins help in the fight. For example, Harry's knowledge of complex spells and Percy's control over water could be used in creative ways to defeat the enemy.
One possible fanfiction could be where Hermione gets jealous when Ron starts spending a lot of time with a new female student in Hogwarts. She starts acting out in class and Ron doesn't understand why at first. Then, Harry has to step in and make Ron realize that Hermione might be feeling left out. This could lead to a big argument between Ron and Hermione which Harry tries to mediate.
In some fanfics, they might be depicted as brothers in some sort of crossover scenario. Fanfic writers often like to create unique relationships between different fictional universes' characters.
There's a fanfic called 'The Quest Beyond Worlds'. It takes Percy and Harry on a cross - universe adventure. It delves deep into the mythology of both series, making it a very engaging read. It also has some great character development for both Percy and Harry as they learn from each other's worlds.
One common theme is competition. Harry, being the main character, often sees Percy as a rival in different aspects such as academic success or recognition within the wizarding community. Another theme is self - doubt. Harry's jealousy makes him question his own worth and abilities. For example, if Percy is getting praise for his work in the Ministry, Harry might wonder if he's doing enough in his fight against Voldemort.