One possible storyline could be a powerful new enemy emerging. This enemy could be a long - lost primordial being. They manage to overpower Percy and Annabeth in a battle that was unexpected. Maybe they were lured into a trap where their powers were nullified, and they couldn't fight back effectively. Another storyline could be a self - sacrifice. For example, to save their friends or the whole of Camp Half - Blood, they choose to face a great danger alone, knowing that they won't survive.
Well, in some fanfictions, it might be due to a curse. A curse placed on them by a vengeful god or goddess. The curse slowly drains their life force until they die. Or perhaps there's a rift in the fabric of their world. They get caught in it while trying to fix it and are torn apart. It could also be that they are poisoned by a magical and incurable substance that was secretly slipped into their food or drink by an enemy within their own ranks.
A fanfiction might have a scenario where Percy and Annabeth die because of a time - related catastrophe. For instance, they travel to a time when the world is ending, and in order to prevent a much greater disaster from spreading across all of time, they have to sacrifice themselves. Or there could be a dark prophecy that foretells their deaths, and no matter how hard they try to avoid it, they end up fulfilling it in a tragic turn of events.
Perhaps they are from rival kingdoms that have been at war for generations. They meet by chance in a neutral territory and instead of fighting, they start to talk. They realize that the war has been caused by misunderstandings between their families. So, they decide to work together to end the war. They face opposition from their own families and kingdoms, but their love for each other gives them the strength to persevere and bring peace.
One possible storyline could be Percy and Annabeth dealing with the emotional aftermath. They might struggle with feelings of guilt and grief. Percy could become overly protective of Annabeth, while she might feel like she has failed in some way. Another storyline could involve them seeking support from their friends in the demigod community, like Grover or Piper, who help them through this difficult time.
One possible storyline could be that in a battle against a new and powerful enemy, Annabeth sacrifices herself to save Percy. Maybe she steps in front of a deadly attack meant for him, like a powerful magic blast from a primordial being. This would shatter Percy, leading him on a journey of both revenge and self - discovery as he tries to come to terms with her loss.
One possible storyline could be their children going on a quest to discover a new hidden part of the demigod world. Maybe they have to find a lost artifact that is crucial for the safety of Camp Half - Blood. Another could be their children facing challenges at school, dealing with both normal school problems and the added pressure of being demigods.
Perhaps they go on a quest to find a way to close the gates of Tartarus permanently. This would involve traveling to different places, facing new monsters, and using their combined knowledge and skills. Along the way, their bond would be tested, and they'd have to rely on each other more than ever, making their relationship even deeper.
One possible storyline could be that their daughter inherits both of their special abilities. For example, she might have Percy's skill with water and Annabeth's strategic mind. She could go on adventures in the same world as her parents, facing new monsters and challenges. Maybe she discovers a long - lost secret related to the gods that her parents were unaware of.
Perhaps in the fanfiction, Weiss dies in a tragic accident. For example, a malfunction in her weapon during a critical moment causes an explosion that she can't avoid. Her death then becomes a catalyst for the rest of the team. Ruby might become more determined to fight against the forces of evil in Weiss's memory. Blake could struggle with guilt, thinking she should have been able to prevent it. Yang might become more reckless in her anger at losing Weiss.
In a fanfiction of Naruto dying of a sickness, perhaps the sickness is a result of overusing his chakra during a great battle. His body starts to break down, and he begins to experience weakness and fainting spells. Hinata, being his wife, is desperate to find a way to save him. She might turn to her own clan's secrets in hopes of finding a cure. At the same time, Naruto tries to train Boruto in what little time he has left, passing on his values and skills, while also coming to terms with the fact that he won't be there to see his son grow up fully.
Perhaps in a more dramatic storyline, Rachel is the victim of some sort of malicious act. Maybe there's a rival at a performing arts school who is jealous of her talent. This person sets up a situation where Rachel is put in danger, like a faulty stage setup during a competition. She gets hurt and later dies, leaving the Glee club to seek justice for her while mourning.
One possible storyline could be that in a final battle against Voldemort, Harry sacrifices himself in a way that no one could reverse. For example, he might use a powerful spell that requires his life force to destroy the last of Voldemort's Horcruxes. Another could be that he succumbs to a dark curse that was placed on him long ago, which was dormant until a certain event triggered it. Maybe a character that was thought to be an ally actually turned out to be a double - agent and cast a fatal spell on Harry.