A really engaging storyline could be them being transported to a different era in the world of Greek mythology. They would have to adapt to the different rules and powers that exist in that time while still relying on their own abilities. This would put their friendship and skills to the test in a whole new and exciting way.
One possible storyline could be the challenges Thalia faces while pregnant in a world full of mythological threats. She might have to rely on her friends more than ever. For example, Percy could be there to protect her from monsters that target her because of her condition. Another could be the emotional turmoil she goes through, as being pregnant might change her role in the group and her own self - perception. She could struggle with how this new situation affects her goals and dreams within the context of the Percy Jackson universe.
One great non - sexual storyline could be about their adventures together in the world of Greek mythology. For example, they might team up to rescue a captured demigod from a powerful monster. Thalia's skills with her spear and Percy's control over water could be combined in an epic battle. Another idea is a story where they are on a quest to find a lost artifact that has the power to save Camp Half - Blood from a new threat. They could face various challenges along the way, like tricky puzzles and dangerous traps.
Some fanfictions might focus on the relationship between the three of them. It could be a story where Percy, Luke, and Thalia are stranded in a strange place. They have to rely on each other to survive. During this time, they start to understand each other better. Percy learns more about Luke's past that made him turn bad in the first place, and Thalia tries to be the mediator between them, leading to a more complex and interesting dynamic.
Perhaps a fanfiction where Percy and Thalia are transported to an alternate dimension. In this new world, they have to figure out how to get back while also dealing with different versions of their friends and enemies. Thalia might have to face an alternate version of herself who has turned evil, and Percy could be the one to help her see the light again. It would be full of action, drama, and self - discovery.
One interesting storyline could be Percy as a baby showing early signs of his demigod powers. Maybe he can control water in his crib, like making the bath water swirl around him in a mini - whirlpool. Another could be the reactions of the gods when they discover this new baby demigod. They might be worried about his potential or already planning how to use him in their future schemes.
There could also be a fanfiction where Percy has to face his inner demons in a more psychological way. Maybe he's haunted by the memories of all the battles he's fought and the friends he's lost. His friends then have to help him through this tough time, and in the process, they learn more about each other's deeper fears and insecurities.
One interesting storyline could be where Percy Jackson somehow ends up in Ariel's underwater world. Maybe he's on a quest that takes him there and he has to team up with Ariel to defeat a common enemy, like a sea monster that is threatening both the underwater kingdom and the surface world that Percy is from.
There could also be a fanfiction where the Hunters take in a new recruit who has a mysterious past. This new character might have powers that are unknown to the world of demigods and the Hunters have to figure out how to train and control these powers. Along the way, they discover that this new recruit is somehow connected to an old prophecy that could change the fate of the demigod world.
One interesting storyline could be a Futa Percy Jackson going on a new quest that involves saving a magical realm from an ancient evil. In this fanfiction, Percy's unique form might give her an edge in combat, like being able to use both male and female - like combat styles.
One interesting storyline could be a crossover where Percy Jackson meets the Crusaders in a modern-day setting. Maybe they have to team up to fight a common enemy that is threatening both the world of Greek mythology and the historical context of the Crusaders. Another could be Percy using his powers in a way that the Crusaders initially misunderstand, leading to some conflict before they realize they can work together.