One possible plotline could be that Percy, Thalia and Nico are betrayed by their closest friends within the demigod community. Maybe they are framed for a crime they didn't commit, like stealing a powerful artifact. This could lead to them being hunted by their own kind. They would then have to go on the run, trying to clear their names while also facing various monsters that are after them because of the false accusations.
In a fanfiction about their betrayal, it could be that they are betrayed by a new character who infiltrates their group. This new character might seem friendly at first but then turns on them to further their own secret agenda, perhaps related to an ancient prophecy. Percy, Nico and Thalia would then have to figure out how to stop this new threat while also clearing their names.
One possible plotline could be that Percy and Nico are betrayed by a close friend within the demigod community. Maybe they are framed for a crime they didn't commit, like stealing a powerful artifact from the gods. This could lead to them being hunted by other demigods while they try to clear their names.
They could be like siblings. Percy and Thalia might act as the older siblings, protecting and guiding Nico. Percy, with his leadership skills, and Thalia, with her combat abilities, would be great at looking out for the younger Nico. They could also be like cousins, with a close - knit bond but still having their own individual family heritages that sometimes create interesting dynamics.
Their relationships would likely become more strained and cautious. Percy, who was always somewhat trusting, might become more guarded. Thalia could become more angry and vengeful, which might put a strain on her relationships with the others. Nico, already a bit of an outsider, might retreat further into himself. They would have to relearn how to trust each other, as the betrayal might make them question if there are any more secrets among them.
Well, they might lose trust in their friends. For example, if they were betrayed by someone they considered a close ally in the demigod world, like a fellow camper at Camp Half - Blood. Percy could become more withdrawn, as he has always been a bit of a loner at heart. Thalia might turn bitter and angry, using her skills as a hunter more aggressively. Nico, being the son of Hades, could potentially be pushed towards using his darker powers in retaliation, perhaps even seeking vengeance in the Underworld's way.
One possible plotline could be that they are in a dangerous situation together, like facing a powerful enemy. In the heat of the moment, their emotions get the best of them and they share a kiss as a sign of their unspoken feelings. Maybe they've been secretly attracted to each other for a long time but haven't admitted it until this high - stakes situation.
One possible theme could be friendship. Despite their different backgrounds and powers, they come together. Percy from Camp Half - Blood, Thalia as a daughter of Zeus, and Nico with his connection to the underworld. Their friendship could be tested and strengthened throughout the story.
A simple betrayal in fanfiction could be that someone they trust gives away their battle plans. So Percy, Nico and Thalia find themselves at a disadvantage during a fight. For example, if they were planning an ambush on a group of monsters and the person who betrays them tells the monsters their plan.
One plotline could be that Nico gets caught in the middle of a powerful magic feud. Percy and Thalia step in, using their unique abilities. Percy with his water - based powers to fend off water - related threats and Thalia with her electric powers. They form a protective shield around Nico as they battle against dark wizards or creatures who want to harm Nico for his own powers.
One challenge is the jealousy of other gods. Since they are new gods, the older, more established gods might not like the attention they get or the new ideas they bring. Another challenge is controlling their powers. As mentioned before, going from demigod to god means a huge jump in power level, and it's not easy to get used to. For example, Percy might accidentally flood a city while trying to create a small puddle for fun.