Well, it could be about Percy having a big showdown with Kronos in a fan - created fictional scenario where he manages to defeat or 'destroy' Kronos. Maybe it involves Percy using his powers, like his control over water, and his combat skills to take on Kronos who is a powerful Titan.
Obviously, Percy and Kronos are the main ones. Percy, the demigod son of Poseidon, is likely to be the hero of the story. Kronos, the powerful Titan, is the antagonist that Percy has to face.
In many fanfictions, Percy might use his water powers in a unique way. Maybe he combines his control over water with his sword fighting skills. He could create a giant water vortex to disorient Kronos and then strike with Riptide while Kronos is off - balance.
Maybe there are some original characters created by the fanfiction author. These characters could have their own unique abilities and backstories. They might be the ones who tip the scales in Percy's favor, for instance, by having a special power that weakens Kronos just before Percy makes the final blow.
Luke could also be a prominent character. Since he has a complex relationship with Kronos in the original story, in fanfiction he could play a role in either helping or hindering fem Percy's efforts against Kronos. Nico di Angelo is another possibility. His powers over the dead could be useful in a fight against Kronos, and he might team up with fem Percy for that reason.
In fanfiction, Kronos's role is not just limited to being a villain. Sometimes, he can be a catalyst for character development among the demigods. His actions force the heroes to become stronger, both physically and mentally. For instance, his threat might make Percy Jackson more determined to master his powers. Also, Kronos can be used to introduce new plot elements, like a new weapon or a magical item that has the power to stop him.
Yes, there are likely some fanfictions out there with this concept. The Percy Jackson fandom is quite large and creative, so it's possible for fans to explore such an interesting and unorthodox relationship in their stories.
One great Kronos fanfiction could be about his backstory before he turned evil. Maybe it explores his relationship with the other Titans and what led him to start the war against the Olympians.
It's possible that the author of the fanfiction wanted to show Percy's growth and development in a more extreme way. So they wrote that Percy had an in - depth understanding of Kronos' weaknesses. He could then use this knowledge to quickly and easily take down Kronos. For example, he might know that a certain spell or attack would be particularly effective against Kronos, and he just exploited that weakness without hesitation.
Some of Kronos' minions, like the monsters he commands, could be antagonists. For instance, the dracaenae. They are always eager to prove themselves to Kronos and might see Percy as competition within Kronos' ranks. They could constantly try to undermine Percy's position and cause trouble for him.