In this type of fanfiction, a plotline could involve Percy being physically tortured in a realm controlled by Kronos. He might be chained up and subjected to various forms of pain. But through the pain, he discovers new aspects of his own strength and heritage. Maybe he has visions during the torture that give him clues on how to defeat Kronos in the end. His friends on the outside are desperately trying to find a way in, and they encounter many obstacles along the way, such as Kronos' minions guarding the entrance to where Percy is held.
Well, perhaps in the fanfiction, Percy is tortured by Kronos in a way that involves his demigod powers being slowly drained. This would make him feel weak and vulnerable, which is a huge contrast to his usual strong self. His torture could also be a way for Kronos to try and break his spirit so that he can turn Percy to his side. Meanwhile, the gods might be debating whether or not to interfere, adding another layer of conflict to the story.
In some fanfictions, Percy's torture in Tartarus could be part of a grander scheme. For example, an enemy on the surface world has made a deal with the forces of Tartarus to weaken Percy. As he endures the torture, he gradually uncovers the conspiracy and tries to find a way to not only escape but also stop those who sent him there. His friends, unaware of his situation at first, start to suspect something is wrong and embark on a quest to find out what happened to him and rescue him.
One possible plotline could be Percy struggling to control Kronos' influence. He might have to fight against Kronos' will to take over his body completely while trying to keep his friends safe.
A great plotline could be Kronos corrupting some of Percy's friends, and Percy having to decide whether to fight them or try to save them first. This adds a moral and emotional conflict to the story. In many fanfictions, this kind of internal struggle makes the story more engaging. For example, Percy might be torn between using his sword on a friend turned enemy or trying to find a way to reverse the corruption.
A plotline could be Percy having to face his own fears and insecurities while being tortured. Maybe he starts to doubt his abilities and heroism. But as the story progresses, he overcomes these doubts through his willpower. Also, the fanfic could explore how the torture affects his relationship with the gods. He might feel betrayed by them for allowing him to end up in Tartarus and this could lead to a change in his loyalty or attitude towards them.
His friends from Camp Half - Blood, like Annabeth, Grover, and Tyson, could be the potential saviors. They have always been by his side and would do anything to rescue him.
One interesting plotline could be Percy having to deal with the conflict of being the son of Kronos while still being a hero. He might struggle with the dark legacy of Kronos within him. Another could be his relationship with Thalia evolving in unique ways, like they team up against a new and powerful enemy that threatens both their existences.
In fanfiction, Percy could become a champion of Kronos due to a complex web of factors. It could start with his disillusionment with the Olympians. After all the battles he's fought for them, if he sees no real change in how they treat demigods or the world in general, he might be open to an alternative. Kronos, being a master manipulator in these alternate stories, could offer Percy power and a chance to truly make a difference. Also, Percy's relationships could play a role. If someone he trusts sides with Kronos and convinces him, or if he's in a situation where he has no other allies and Kronos offers support, he could end up in that role. But these are all departures from his original character in the official Percy Jackson series.
Well, one possible consequence could be that Percy gains an immense amount of power. Kronos was a very powerful Titan, so Percy might become nearly invincible. He could also face some internal struggles as Kronos' essence might try to influence his mind and actions.
In the fanfiction, Kronos may be presented as having a more complex personality. His actions that seemed evil in the original story could be a means to an end. For example, he might have been trying to save the Titan race from extinction at the hands of the gods, which is a valid reason and thus makes him not purely evil in the context of the fanfiction.
One possible plotline could be that Shield has been corrupted in this fanfiction. Maybe they see Percy as a threat to their new order or some secret project. They might use his demigod powers against him, perhaps by using some high - tech device that messes with his connection to the gods. This could lead to Percy being physically and mentally tortured as he tries to resist and figure out a way to break free.