In the fanfiction, it could be that Percy and Thalia have a long - established friendship. Jason, being new to their group or dynamic, might feel like he can't break into that bond. He may see how they rely on each other and communicate without words, and he wishes he could be part of that. The jealousy then stems from his desire to be as close to them as they are to each other.
Well, it could be that in the fanfiction, Percy and Thalia are both really popular and well - liked among their peers. Jason, on the other hand, might feel overshadowed by them. He's jealous because they seem to get all the attention and admiration, while he feels like he has to struggle more to be noticed.
It can add a lot of drama to the story. For example, Jason's jealousy might lead to him making rash decisions. He could try to compete with Percy and Thalia in a way that causes problems for their group. This might create conflicts that they have to resolve, making the story more interesting.
One reason could be Jason's popularity. Maybe Jason is getting more attention from their peers or the gods, which makes Percy jealous. Another might be related to a girl they both like. If the girl shows more interest in Jason, Percy could feel jealous.
In the fanfic, it could be that Percy and Thalia have a certain level of trust and understanding that Jason lacks with either of them. For example, they might communicate in a way that Jason wishes he could with them. Percy's relationship with the gods, especially Poseidon, and Thalia's connection to Zeus might make them a more formidable and enviable pair in Jason's eyes. He may be jealous of the power dynamics and the way they interact within the story.
In such a fanfiction, Jason might be jealous because Percy has a strong connection with the sea and Thalia is a powerful daughter of Zeus. Maybe Jason feels overshadowed. For example, Percy's feats in the ocean make him stand out, and Thalia's leadership skills are remarkable. Jason could be jealous of the attention they get.
One reason could be Percy's popularity. Percy has many friends and is well - liked in the demigod community. Jason might feel overshadowed by Percy's charisma and the attention he gets.
Well, it might be that Percy has a more carefree attitude in some ways. He doesn't always follow the rules strictly and still manages to come out on top. Jason, who is more of a rule - follower and leader type, might envy Percy's ability to bend the rules and get away with it. Plus, Percy has a closer connection to Camp Half - Blood which has been his home for a long time, while Jason has to adjust to this new place and community, seeing Percy so well - integrated can make him jealous.
Maybe Jason feels overshadowed by Percy. Percy's powers are quite remarkable and Jason might think that Percy gets more attention because of them.
The jealousy could lead to a split in the group. If Jason is constantly jealous, he may distance himself from Percy and Thalia, which would change the group dynamics. This could then lead to new alliances and rivalries within the fanfiction. Maybe Jason teams up with other characters who also feel left out because of Percy and Thalia's popularity.
One reason could be competition for a girl. Maybe they both have feelings for the same female character in the story, like Annabeth, and Jason's jealousy over Percy's relationship with her leads to a fight.