Well, perhaps the fight could be physical. Percy could summon water to try and surround Thalia while she calls on lightning to strike at Percy. Their powers would create a chaotic scene. However, in the end, they might realize they've been played by a common enemy who wants to see them divided, and then they team up again.
In a fanfic about Percy and Thalia's fight, it could start because of a misunderstanding. Maybe Thalia thinks Percy is getting too much attention from the gods and she's jealous for the sake of all the half - bloods. Percy, on the other hand, might not understand why Thalia is so hostile all of a sudden.
It could also be an argument - type fight. Thalia might accuse Percy of being reckless and endangering the whole camp with his actions. Percy would defend himself, saying he's just trying to protect everyone. This could lead to a tense exchange of words until one of them realizes they're both on the same side and should be working together.
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.
A Percy and Nico fight in fanfiction might be a complex affair. Their respective loyalties could come into play. Percy is loyal to Camp Half - Blood and Nico has his own complex allegiances. They could be fighting because of different ideas about how to deal with a new threat to the demigod world. Percy might think of a more upfront approach using his powers, while Nico could be more inclined towards using his knowledge of the Underworld and the dead to outwit the threat. This difference in approach could lead to a fight between them as they try to impose their methods on each other.
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 Percy could become more withdrawn, as he has always been a bit of a loner at heart.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.
In a fanfiction where they go to high school, Percy would likely be popular for his heroic deeds and good looks. He might join the swim team and break all the records. Thalia could be the cool girl who rides a motorcycle to school and gets into trouble for parking it in the wrong place. Nico would be the mysterious new kid. There could be a plot where they have to team up to stop a monster that is lurking in the school basement.
In the fanfiction, they could be given important missions. Maybe they are tasked with restoring balance in a part of the Chaos realm that has been thrown into disorder. Percy's leadership skills, Thalia's combat experience, and Nico's knowledge of the underworld could all be put to good use. They would have to work together, which might not be easy at first given their different personalities. But as they face challenges, they would grow closer and become a more effective team.
They could be sent on epic quests by Chaos. Maybe they have to retrieve some powerful artifacts that were lost in the chaos of creation. Along the way, they would face numerous challenges and meet all kinds of strange creatures. Percy would use his strategic thinking, Nico his knowledge of the underworld, and Thalia her leadership skills to overcome obstacles and make their way towards their goal.
A simple plot could be a race against time. They have to reach a certain place before an evil force does. Thalia could use her speed and strength, Percy could use his strategic thinking as a champion, and Zoe could use her knowledge of the terrain to lead them. They might encounter traps and minions of the evil force along the way.
It might also be a story about their relationships. Perhaps there are tensions between them at first. Percy's status as a champion might make Thalia a bit jealous or Zoe might be skeptical of his abilities. But as the story progresses, they learn to trust and rely on each other, forging a strong friendship.
A fight with bandits in the city fanfic could have all sorts of exciting things. Maybe the bandits have a hidden agenda, or the fight leads to uncovering a big conspiracy in the city. It could also focus on the emotional journey of the characters involved in the battle.
In fanfiction, they might have an epic adventure. Percy could use his water powers to protect them if they encounter any danger. Thalia with her lightning might strike down foes. Nico could summon the dead to get information. Rhea might offer them some ancient wisdom or a special quest to save the world.