Obviously, Percy would be a main character, now as a daughter of Artemis. Artemis herself would also be a very important character, as Percy's new 'parent' in a sense. Annabeth could still be a main character too, as her relationship with Percy would likely change and be explored in the fanfiction.
Perhaps a plotline where Percy, as the daughter of Artemis, is chosen for a special mission. The gods, seeing her unique heritage, task her with something that no other demigod can do. It could be related to restoring balance in the world of the gods. Along the way, she has to deal with her own insecurities about not being a 'normal' demigod and prove herself worthy of the mission.
In this fanfiction, she could also have special powers related to Artemis. Such as enhanced archery skills, the ability to communicate with animals, and a strong connection to the moon. Her adventures might involve using these powers to protect the camp or to go on quests that are related to the moon goddess's domain.
One possible plotline could be Percy struggling with the new identity within the context of Artemis' Hunters. For example, she might have to deal with the strict code of the Hunters while still having her own personality traits from being Percy. Another could be her relationships with other characters like Annabeth, who might have a different dynamic now that Percy is part of Artemis' group.
She might be on a quest to retrieve a lost artifact of Artemis. This could involve traveling to different mythological locations, facing monsters along the way. Her skills as a daughter of Artemis, like her archery and tracking abilities, would be crucial in this journey.
There could also be a group of rogue demigods who oppose the daughter of Artemis. They might be jealous of her powers or her connection to Artemis. They could try to sabotage her and Percy's quests and cause trouble for them at every turn.
Well, if Percy was the daughter of Artemis, she'd likely be more in tune with nature. The original Percy was more associated with the sea, but this new Percy would have a stronger connection to the forests and wild animals. She might also be more reserved and independent, like Artemis. Artemis values her solitude and freedom, and Percy as her daughter might inherit those traits, being less likely to rely on a big group of friends compared to the original Percy.
One idea could be that the daughter of Artemis has unique archery skills that she uses to protect Percy during a dangerous quest. Maybe she can communicate with animals in a special way, like her mother, which helps them gather information or escape from enemies.
At first, their relationship might be rocky. Percy is used to his own way of doing things and Artemis' daughter is bound by her mother's values. But as they face challenges together, like fighting monsters or solving mysteries, they start to respect each other. Eventually, they could become good friends who trust and rely on one another.