One plotline could be the overprotective brother constantly trying to keep Percy out of dangerous quests. He might try to interfere with Chiron's plans for Percy, thinking he's too young or inexperienced. Another could be the brother getting into arguments with Percy's friends like Annabeth when he feels they're leading Percy into harm's way. And there could also be a plot where the brother himself gets involved in a quest to protect Percy and discovers his own hidden powers along the way.
Well, the overprotective brother could be a new character added to the Percy Jackson universe in this fanfiction. He might be from a different godly parentage. His overprotectiveness could stem from a prophecy he heard about Percy. For example, he heard that Percy will face a great and almost unbeatable foe in a particular place. So, he tries to keep Percy away from that location at all costs. He could also be overprotective because Percy is the only family he has left. So, he would do anything to keep Percy safe, even if it means sacrificing his own well - being.
One possible plotline could be Percy struggling to keep his cancer a secret from his demigod friends while still trying to go on quests. He might worry that his weakened state due to cancer will let them down. Another could be Percy using his demigod powers in a unique way to fight the cancer, like trying to find a magical cure in the realms he can access. Maybe he discovers some ancient herb or potion that has the potential to heal him, but he has to face many challenges to obtain it.
Another interesting plot could be Percy's internal struggle. He's used to being Poseidon's son, and now this new connection to Styx throws his identity into a bit of chaos. He has to figure out how to balance his old self with this new aspect of his being, all while facing various quests and threats in the Percy Jackson universe.
One possible plotline could be Naruto protecting his younger sibling from the threats of rogue ninjas. He would use his skills and influence in the ninja world to keep them safe, perhaps even training them secretly to ensure they can defend themselves. Another plotline might involve Naruto dealing with a political situation where his sibling is in danger due to their relation to him. He has to navigate the complex world of ninja politics to safeguard his family.
A son of Athena could also work well. Athena is the goddess of wisdom, so her son would be intelligent and strategic. He could use his intelligence to plan ways to keep Percy out of trouble. He might be overprotective because he sees Percy's potential but also the naivete that comes with being young, and he wants to guide Percy in the right direction.
One plotline could be Percy having flashbacks during a normal day at Camp Half - Blood. For example, while training new demigods, he suddenly remembers a particularly harrowing battle from the past. This could lead to him accidentally losing control of his powers a bit, scaring the newbies. Another could be Annabeth having nightmares about the time she was trapped in Tartarus. In the fanfiction, she might start avoiding places or activities that remind her of it, like going underground or exploring dark caves. And a third plotline could be them both trying to deal with their PTSD while on a new quest, where they have to rely on each other more than ever to overcome their mental struggles.
One interesting plotline could be the Seven facing a new, more powerful enemy that is a combination of different mythological creatures. This would test their teamwork and individual powers in new ways.
One interesting plotline could be Aphrodite taking a special interest in Percy for a quest related to love and beauty. Maybe she tasks him with finding a lost artifact that has the power to enhance or destroy love. Another could be Percy falling under a love spell cast by Aphrodite, which causes chaos among his friends as he starts acting out of character. And a third one might be Aphrodite using Percy as a pawn in a love - related game among the gods, where his actions and decisions have far - reaching consequences for the relationships between the deities.
One interesting plotline could be the siblings going on a secret quest together without the knowledge of Chiron or the other campers. They might face a new and unknown monster that tests their combined skills.
In some fanfictions, a centurion discovers a long - lost prophecy that involves Percy. This could lead to a race against time as they try to figure out the meaning of the prophecy and prevent a great disaster. Maybe it involves a new Titan rising and they need Percy's unique connection to the sea gods to stop it.
Maybe in the fanfiction, Percy's player side shows up when he has to navigate the complex social hierarchies of the demigod world. He could be seen charming different groups of demigods, from the children of Athena with his quick - witted remarks to the children of Aphrodite with his newfound 'player' charisma. This could lead to all sorts of adventures and conflicts as he tries to maintain his relationships while also keeping up his player image.