Well, it could be about a misunderstanding. Maybe there's a rumor that Percy has done something bad to Jason's friends, so Jason challenges him to a fight. Percy, being Percy, doesn't back down and they start fighting. In the end, they realize it was all a big misunderstanding when the real culprit is found.
Perhaps it's a fight for leadership. In a camp where both Percy and Jason are respected leaders, there's a competition for a top position. Their followers start taking sides and it escalates into a physical fight between the two. But then they both come to their senses and decide to share the leadership instead of fighting over it.
Maybe they end up in a draw. They both are strong in their own ways. Jason has his lightning powers and leadership skills. They might fight to a point where neither can gain an upper hand and decide to call it a tie.
It might be a test of strength. They could both be trying to prove themselves, either to their friends or to some higher power in the fanfiction world. They want to see who is truly the stronger hero.
Well, it could be about a misunderstanding. Maybe Percy accidentally uses his powers in a way that Thalia misinterprets as a threat to her leadership among the demigods. So she lashes out at him, and Percy, not one to back down easily, fights back.
The plot might involve Percy and Jason having to adapt to the new and chaotic rules of the Chaos realm. They could discover new powers within themselves as they are exposed to the wild and unpredictable energy there. They might also meet old enemies who have also found their way into this strange new world, leading to some epic battles and unexpected alliances.
Perhaps in the fanfiction, Percy is under some sort of dark influence. This could be from a new, unknown magical force. This influence makes him see Jason as a threat to his friends or himself, so he attacks Jason. Jason, on the other hand, is initially confused but then tries to fight back to defend himself while also trying to figure out what's wrong with Percy.
One possible plot could be that Jason is really shy about his crush at first. He tries to be around Percy more often, like joining the same quests or training sessions. He might secretly do nice things for Percy, like leaving his favorite food at his cabin without saying who it's from.
Well, in a fight between Percy Jackson and Jason Grace in a fanfiction, Percy could use his water powers to his advantage. He might create huge waves or even use water to disorient Jason. Jason, on the other hand, would likely call upon the winds and lightning. He could try to strike Percy with lightning bolts while using the wind to keep Percy's water attacks at bay. It would be an epic battle of the elements.
In a 'percy and jason fight fanfiction', the winner could depend on their mental state. If Percy is more focused and determined, he might be able to outwit Jason. On the other hand, if Jason is more confident and has a better strategy, he could win. Also, their allies could play a role. If Percy has more of his friends to back him up and provide distractions, he could emerge victorious. But if Jason has his crew helping him in a smart way, he might win.
In a 'Jason meets Percy' fanfic, they could meet in a place that is neutral to both of them, like a magical marketplace. Percy is there looking for a special item for his next adventure, and Jason is on a mission to find a way to strengthen his camp. They cross paths and initially have a bit of a misunderstanding. But as they start talking, they find out they have a common enemy in the background planning something big. So they decide to join forces and use their unique skills to stop the enemy.
Maybe in the fanfic, there is a tournament in their world, and Jason and Percy are both participants. Before the actual tournament, they decide to spar with each other to test their mettle. Along the way, they face some challenges like disagreements on the rules of sparring or external distractions, but they work through them.