If Percy Jackson joins Kronos in fanfiction, it would be a huge deviation from the original story. Percy is a hero who stands for good, and Kronos is a villain. This could lead to a very dark and twisted version of the Percy Jackson universe, with Percy using his powers to aid Kronos in his evil plans, perhaps causing chaos among the gods and other demigods.
The story would be very different. The loyalty of the other characters would be tested. For example, Annabeth might be heartbroken and try to bring Percy back to the right side. Also, the gods would be in a much more difficult situation as they face a combined threat of Percy and Kronos.
In a fanfic scenario where Percy Jackson joins Kronos, it could be a very interesting exploration of the 'what - ifs'. Percy has a strong sense of justice, so for him to side with Kronos, Kronos must have presented a very convincing argument. It could be that Kronos showed Percy a future where the demigods are constantly oppressed by the Olympians. However, this would also mean Percy has to go against his instincts and the relationships he has built. His friends like Annabeth would be in shock and try to bring him back to the right side. This could lead to some intense battles not only between the demigods and Kronos' forces but also within Percy himself as he struggles with his new allegiance.
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.
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.
It's very possible. Fanfiction is a creative space where all kinds of ideas are explored. The idea of Percy serving Kronos goes against the typical hero - villain dynamic in the original series. But that's what makes fanfiction so exciting. Writers can twist and turn the established lore in new and fascinating ways. You could start your search by using specific tags related to Percy, Kronos, and the Percy Jackson series on fanfiction platforms.