Well, perhaps in the fanfiction, Hecate decides to train Percy in the ways of magic. Since Percy already has his own powers, this could lead to some really cool combinations. For example, he could learn to use his water powers in conjunction with Hecate's magic of illusions. Or, there could be a story where Hecate's dark side is awakened and Percy has to stop her from causing chaos, but also has to find a way to save her from herself.
One idea could be Percy seeking help from Hecate to break a powerful curse that has been placed on Camp Half - Blood. Another could be Hecate tasking Percy with a quest to retrieve a magical artifact that she needs to maintain the balance of magic in the world. Maybe Percy has to enter the realm of Hecate and face various magical trials to gain a new power.
One idea could be that the daughter of Hecate uses her magic to help Percy in a quest that involves navigating through a magical maze. She could create illusions to deceive the monsters inside.
One idea could be Percy having to master Hecate - related magic to defeat a new type of monster that is immune to physical attacks. Another could be Percy being chosen by Hecate to retrieve a powerful magical artifact from the underworld. And perhaps Percy must use Hecate's magic to save his friends who have been trapped in a magical maze created by an old enemy.
Another plot could involve Percy's relationship with other children of Hecate. Maybe there's a group of them that he has to lead in a battle against a common enemy. This would explore his leadership skills as well as his connection to his Hecate - related heritage. He might have to learn some ancient spells from them to defeat the foe.
One interesting plot idea could be the OC using their Hecate - given powers to manipulate the Mist in unique ways. For example, creating illusions not just to deceive enemies but also to solve puzzles within the Percy Jackson universe. Maybe there's a quest where they have to use their magic to uncover hidden paths in an ancient labyrinth that's been magically altered by another deity.
Well, perhaps in the fanfiction, Percy is on a quest that involves an ancient magic artifact that is closely tied to Hecate. As he tries to find it, he has to enlist Hecate's help. Along the way, they face many enemies together and start to see each other in a new light. They might share some tender moments during their battles and while exploring the secrets related to the artifact.
Well, a plot could involve Percy getting caught in a magical feud between different factions related to Hecate. He might have to use his combat skills along with his newfound magical abilities to resolve the situation. Also, a story where Percy has to protect a sacred place related to Hecate from monsters would be interesting. He could learn about the secrets of Hecate's magic in the process.
One possible plot could be Percy discovering new powers bestowed upon him by Hecate. He might have to use these powers to navigate a mysterious underworld realm filled with strange creatures. Along the way, he could meet new allies who are also under Hecate's influence.
Well, one possible plot could be Percy discovering new powers. Since Hecate is the goddess of magic, Percy might learn magical abilities he never knew he had. Maybe he starts to see magic in everyday things in a way he didn't before. For example, he could make inanimate objects come to life or use spells to protect himself and his friends. Another aspect could be his relationship with Hecate. She might be a strict but loving mother figure, teaching him about the deeper mysteries of the demigod world and how magic fits into it all.
One plot idea could be Percy having to team up with Hera to rescue a group of demigods who have been captured by an ancient monster. Hera, despite her usual aloofness, realizes she needs Percy's unique skills.
The plot could also be about the daughter of Hecate uncovering a dark magic plot that endangers Camp Half - Blood. She initially tries to handle it on her own but realizes she needs help. Percy Jackson gets involved and they start to investigate. Along the way, they discover that the source of the problem is an ancient curse related to Hecate herself. The daughter has to come to terms with her heritage and use her powers in ways she never thought possible to break the curse and save the camp.