I think Percy Jackson himself would be really interesting. He has such a strong personality and his powers are unique. In a fanfiction with Descendants, he could bring his demigod skills and his sense of adventure. He might be a bit of a fish out of water in the Descendants' world, which could lead to some really funny and exciting situations. His loyalty and determination would also make him a great character to drive the story forward.
Annabeth Chase would also be a great choice. Her intelligence and strategic thinking would be valuable in the world of Descendants. She could analyze the different situations in the Descendants' world in a way that the other characters might not. Also, her relationship with Percy could add an extra layer of drama and romance. She could help the Descendants with their problems using her wisdom, while also learning about their unique magic and culture.
I think Mal from Descendants would be really interesting. If you combine her with the Percy Jackson universe, her skills in magic and her somewhat villainous past could create a lot of drama. She could be a bit of an outcast among the demigods at first because of her heritage, but then prove herself as a valuable ally. For example, she could use her magic to help the demigods in a battle against a new type of monster that is resistant to normal demigod powers.
Annabeth Chase could be an interesting character to focus on. She is highly intelligent and strategic. In a crossover, she could use her knowledge of architecture and battle strategies to help Eragon and his allies. She might study the magic in Alagaesia and find similarities or differences with the powers of the demigods. Her relationship with Percy could also be explored in a new light, especially when they are in a completely different world. How would they support each other in this new and strange environment? And how would she interact with the characters in Eragon's world?
Percy would be really interesting. His skills and experiences are so diverse. He could consider so many different careers like being a hero - which he already kind of is - or he could use his swimming skills for something like marine rescue. He has a great sense of adventure which could lead him to explore different career paths that are both exciting and useful.
Annabeth Chase would be an exciting character to center on. Her intelligence and strategic thinking would be a great asset in the maze. She could quickly analyze the layout of the maze and come up with plans. She might also be the one to bridge the gap between the two groups, as she's good at understanding different people and situations. Her knowledge of architecture and mazes from her own world could be applied to solving the mysteries of the Maze Runner's maze. And her relationship with Percy would add an extra layer of drama, especially when dealing with the new and dangerous situations in the crossover world.
I think one of the AHS swim team members who is really skeptical at first about Percy's claims of being a demigod could be an interesting focus. As they start to see evidence of the supernatural world, their journey from disbelief to belief and their growth in understanding would be great to explore. They could also develop a strong friendship with Percy along the way.
Percy Jackson and Mal would be an interesting pair. Percy has his water powers and his heroic, yet sometimes impulsive nature. Mal has her magic and her complex background as a VK. They could learn a lot from each other. Percy could show Mal that not all heroes are born into perfect situations, and Mal could introduce Percy to the different kinds of magic in the Descendants world.
Nico di Angelo would be an interesting choice. His dark and brooding nature along with his powers over the dead would be a contrast to the more light - hearted aspects of the Harry Potter world in some ways. He could introduce the wizards to the concept of the Underworld and the spirits. And his ability to shadow - travel could be used in some really creative ways, like getting the group in and out of dangerous situations quickly, whether it's in Hogwarts or in the magical areas related to Greek mythology.
Annabeth from Percy Jackson could be really interesting. She's smart and strategic. In a crossover, she could be the one to figure out how the H2O girls' powers work and how they can be used to everyone's advantage. Also, Cleo from H2O has her own charm. She comes from a different background and her insecurities combined with Annabeth's confidence would make for great character development.
Percy and Annabeth are always interesting. Their relationship is central to the series, and in the House of Hades, they face extreme challenges that can be explored further. Their love and loyalty to each other can be put to the test in different ways. For example, when they are separated, how do they each cope and still strive towards their common goal? Another interesting character is Nico. He has a deep connection to the underworld and his own complex backstory. In the House of Hades, his powers and knowledge could be further developed in fanfiction.
Percy and Annabeth are always interesting to focus on. Their relationship is central to the story, and in the House of Hades, there are so many opportunities to explore their bond further. They are both strong, yet vulnerable in different ways. Nico di Angelo is also a great character to focus on. His past and his connection to the underworld give him a unique perspective. Plus, his powers are really cool. Another interesting character could be Bob, the Titan. He has a complex personality and his loyalty to Percy and the others adds an interesting dynamic.