One common theme is friendship turning into something more. Since they start as comrades, the fanfics often show the gradual shift in their relationship. For example, in many stories, they first bond over their shared experiences in battles and then realize their deeper feelings.
One great Jason and Percy lemon fanfic is 'Sun and Sea'. It beautifully weaves their characters together in an adventure-filled story. The chemistry between them is well-portrayed, and the writing style is engaging.
The unique character dynamics. Percy, Nico, and Jason all have distinct personalities. Percy is brave and impulsive, Nico is dark and brooding, and Jason is more of a leader type. When combined in a fic, their interactions can be really engaging.
It could be that the author of the fanfic has created a rivalry between them. In some fanfics, authors like to add tension and conflict, and Jason hating Percy could be part of that. Maybe Percy got more attention or praise in the story, and Jason, being a proud character, resents that.
I'm not sure of specific 'percy x nico x jason lemon fanfic' titles off - hand. But you can try searching on fanfiction - dedicated websites like Archive of Our Own. They usually have a wide range of fan - fictions, and you can use the relevant tags to narrow down your search.
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.
It could be an old enemy from their past, like a resurrected Titan or Giant. These powerful foes might manipulate Percy and Jason into betraying their friends as part of a grand plan to regain power or take revenge on the demigods.
Another theme is adventure. Since they are from the world of Greek mythology, they go on quests together. These quests test their abilities and strengthen their relationship. They might be searching for a lost artifact or trying to defeat a powerful monster.
One possible consequence is that it could lead to a split in their group. If they are part of a team or a community, their animosity could cause others to take sides, creating factions.
Well, it really depends on the context of the fanfic. If it's near water, Percy has a huge advantage as he can control water and heal himself with it. But Jason is no slouch either, he can control the winds and lightning. However, in many fan interpretations, Percy's combat experience and his ability to improvise might give him the edge.