There are also minor characters that can become popular in these fanfictions. For instance, the centaurs from Camp Half - Blood. They could be training fem Percy in new combat techniques or providing her with ancient knowledge that is relevant to fighting Kronos. Or the gods themselves could be more involved, like Athena guiding fem Percy in a more direct way compared to the original story, which would add an interesting layer to the fanfiction.
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.
Obviously, Percy Jackson is one of the main characters. He is the demigod hero with his own set of powers and a strong sense of justice. And then there's Fem Kronos. She is a female version of the powerful Titan Kronos. Her character might have different motives and ways of operating compared to the male Kronos we know from the original myths. There could also be other characters like Annabeth, Percy's friend and strategic partner, who might play a role in the fanfiction, either helping Percy against Fem Kronos or getting caught in the middle of their conflict.
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.
Annabeth is often a popular character. In fanfiction, she might play a crucial role in helping Percy deal with his complex identity as the son of Kronos. Grover could also be popular as he's Percy's loyal friend and could be there to support Percy through his struggles related to his new - found heritage.
Kronos is also a popular character. His menacing presence and his complex backstory attract a lot of writers. Writers like to explore his motives for rebelling against the Olympians and what made him turn into such a villain.
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.
I'm not sure of a specific title, but in general, these types of fanfictions often explore how being Kronos' daughter would make her an outcast among the other demigods. They might also show her coming to terms with her father's actions and trying to make a name for herself separate from his dark legacy. You could search on popular fanfiction sites using relevant tags like 'fem Percy', 'Kronos' and 'daughter' to find some good reads.
A possible plot is that fem Percy is sent on a quest that is somehow related to Kronos. Along the way, she discovers secrets about Kronos' past that she can use to her advantage. She might also meet characters who knew Kronos before he became the big bad, and these characters help her in her fight against him. For example, she could find an ancient weapon that was once used against Kronos and learn how to wield it effectively.
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.
His friends like Annabeth might come to his rescue. Annabeth is smart and resourceful, she could figure out where Percy is being held and lead a rescue mission.
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.