Maybe Percy leaves the hunt because he has some personal issues to deal with. For example, he might have a family matter that requires his full attention. Or perhaps he has a different mission or goal in mind that conflicts with the hunt.
There could be his friends or comrades in the hunt. For instance, someone like Annabeth who might be affected by his leaving and try to convince him to stay.
Since it's a fanfic, the plot could vary widely. It could be that Percy is on a hunt and the lemon aspect is a unique addition by the author. For example, the lemons could have magical properties in this fanfic world. Percy might be using them to solve puzzles or fend off enemies during the hunt. Without reading it, it's hard to say for sure.
In a 'percy adopted by the hunt fanfic', it could start with Percy being an outcast in his own world. The Hunt, seeing his potential, adopts him. He is then introduced to a whole new world of magic and mystery that the Hunt is a part of. He has to bond with the other members, which isn't easy as they are a tight - knit group. Percy may also bring new ideas to the Hunt, based on his own unique experiences, and together they embark on adventures that neither Percy nor the Hunt could have imagined on their own.
One possibility could be that Percy leaves camp to go on a solo quest to find a long - lost magical artifact that he believes can save the camp from an upcoming threat. He might face many challenges on his own, like battling new monsters and making difficult decisions without the support of his friends at camp.
One possible motive could be a misunderstanding. Maybe the Hunt has been misinterpreted as a threat to Percy's friends or Camp Half - Blood. So in his attempt to protect his own, he takes extreme action.
One possible plot development could be Percy feeling extremely hurt and isolated after the betrayal. He might go off on his own to find a way to prove his worth again. Maybe he'll encounter some old enemies who now see him as vulnerable and try to take advantage of his situation.
Well, perhaps in the fanfiction, Annabeth could initially be in denial about being pregnant after Percy leaves. But as time goes on, she starts to accept it and decides to focus on building a better future for her and the baby. She might also get support from her friends like Grover, who could help her out in various ways, such as finding a safe place to stay and providing emotional support.
One possible plot development could be Naruto leaving due to a misunderstanding. For example, if he is wrongly accused of a crime within the team. Another could be that he feels he is holding the team back in some way and decides to leave on his own to become stronger alone. Maybe he has a personal goal that he believes he can't achieve while still being part of Team 7.
One possible plot could be that Castle's father left behind some mysterious clues before disappearing. Castle, along with his friends or family members, starts to hunt for these clues all over the city. They might visit his old haunts like an old library where he used to study or a secret club he was part of. As they dig deeper, they start to uncover secrets about his past that Castle never knew, like his involvement in a long - forgotten case or a secret society.
One idea could be Percy being reluctantly recruited by the Hunt. He has to learn their ways while still holding onto his own identity. Maybe he discovers a new power related to the Hunt that no one expected.