Well, it could be that there's some sort of magic or illusion at play. Jason might be seeing Percy as a god because he's been influenced by an external force. This external force could be an enemy trying to create chaos by making the other demigods believe Percy is a god. And Percy has to then figure out what's going on and clear his name while also dealing with the new - found respect or fear from his peers.
Some characters might be in awe of Percy. For example, Annabeth could be both proud and a little bit worried. Proud because Percy has reached what seems like a new level of power, but worried about how this new status will change him and their relationship. Grover, on the other hand, would probably be very excited. He's always been Percy's loyal friend and seeing Percy as a god - like figure would make him feel even more special to be associated with Percy.
One popular plot twist is when they end up swapping powers. Percy suddenly has control over wind and lightning while Jason can control water. This flips the script and makes for some really interesting scenarios.
A great plot twist could be that they are both being manipulated by a third force. They think they are fighting each other for their own reasons but in reality, they are being used. Maybe a god or a powerful demigod is pulling the strings. This would lead to a moment of realization and then they would have to figure out how to work together to stop the real threat. Also, a plot twist where the Mark of Athena has a different meaning for each of them could be really engaging. It could be that Percy thinks it means one thing and Jason thinks it means another and their interpretations lead to a big misunderstanding before they figure it out.
Another possible plot twist is that their sparring somehow awakens an ancient prophecy. They initially think it's just a normal sparring session, but then strange signs start to appear. For example, old symbols start to glow on the ground around them as they spar. They then have to figure out what this prophecy means and how their sparring is related to it, all while still dealing with their friendly competition.
One interesting plot twist could be that Percy is mistaken for a god by a group of mortals who then start to worship him. This leads to Percy having to deal with the moral dilemma of whether to let them continue or reveal his true identity. Another could be that a real god gets jealous of Percy being mistaken for one and tries to frame him for something bad.
Maybe in the fanfiction, Percy is tricked into becoming a god. A powerful enemy disguises as a friend and makes Percy perform a ritual that he thinks is for saving his friends but actually turns him into a god. Percy then has to deal with new powers he doesn't fully understand and the betrayal of those who deceived him.
One possible plot twist could be that Percy is initially oblivious to Jason's feelings. Then, just when Jason is about to give up, Percy discovers his own hidden feelings for Jason. Another twist could be that there's some external force, like a god or a prophecy, that tries to keep them apart. Or perhaps Jason discovers that Percy has a pre - existing relationship that he didn't know about, which complicates his crush.
A major plot twist might be that the other gods, not happy with Percy dating Aphrodite, try to separate them. Maybe they create false rumors about Percy to turn Aphrodite against him. Or perhaps Percy's new godly powers start to fade when he gets too involved with Aphrodite, and he has to figure out how to balance love and power. There could also be a twist where Aphrodite's true form is revealed to be something that Percy didn't expect, which shakes their relationship.
Well, a possible plot twist is that their powers combine during the fight. Like, Percy's water and Jason's lightning create some sort of new, powerful energy that neither of them can control at first. This could lead to them having to work together to contain it. Another plot twist could be that the fight is a dream or a vision, and they both wake up in different places realizing that they need to prevent this fight from happening in the real world. And perhaps there's a prophecy that says one of them must die in this fight, but they find a way to change the prophecy during the battle.
Well, in such a fanfic, it could be that Jason believes he has certain skills or qualities that Percy lacks. Maybe Jason thinks his leadership in the Roman camp gives him an edge. For example, his military strategies might seem superior in his own eyes.