One possibility is that the sister has some unique powers that the Olympians fear. So they abandon her. In the fanfiction, she could be on a journey to discover her true self and her powers, while Percy unknowingly gets involved in her quest. Maybe she's being hunted by some mythical creatures because of her heritage, and Percy has to save her in the end.
It could be a vengeful god. Maybe a god who feels that the sister's existence is an insult to their power. So they set out to stop Percy from finding her. For example, Hades might be the antagonist if he believes that the sister's return could disrupt the order in the Underworld.
Percy would likely be very confused at first. He'd probably feel a mix of anger and sadness. He might start to question his own actions and wonder if he did something wrong to make his sister leave.
One possible plot could be Percy feeling a deep sense of betrayal and loneliness. He might struggle with his self - worth as he wonders why his sister left him. This could lead him on a journey to find answers about his family and his own identity, perhaps even uncovering secrets about his demigod heritage that his sister knew and he didn't.
Well, it depends on how the fanfiction is written. But generally, yes, Percy Jackson can be part of the Hunt fanfiction. Fanfiction allows for a great deal of flexibility. In the context of the Hunt, if it has elements of mythology or a need for a hero - like figure, Percy Jackson would be a great fit. His backstory as a son of Poseidon gives him a rich source of material to draw from. He has faced numerous challenges in his own series, and these experiences can be translated into the Hunt fanfiction. For instance, his knowledge of the mythological world and his combat skills could be used to further the plot in a Hunt fanfiction where he teams up with the Hunt characters to achieve a common goal.
Artemis could be seen as the 'guardian of the hunt' in Percy Jackson fanfiction. As the goddess of the hunt in Greek mythology, she has the power and the authority to oversee everything related to the hunt. She could be the ultimate protector of the hunters and the hunting grounds.
Perhaps she's a sister who was thought to be dead but actually survived. She could have been corrupted by the experiences she had while being 'dead'. When she returns, she blames Percy for not saving her properly. This false blame leads her to betray Percy. She could start spreading rumors about Percy being a coward or a bad leader among the demigod community.
One common theme is the clash of different worlds. Percy, coming from his own world of demigods, enters the realm of Artemis's hunt. This often leads to misunderstandings and challenges as the two groups have different rules and cultures.
In this fanfiction, Percy might face a series of challenges. Maybe he has to use his unique demigod skills to try and escape. The Hunt is a powerful group, so he could be in for a tough time.
Obviously, Percy Jackson is a key character. Then there would be the members of the Hunt. Artemis, the goddess leading the Hunt, would also be an important figure in the story, even if she may not be directly involved in the capture but her influence over the Hunt is significant.