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.
Perhaps it starts as a misunderstanding. Percy might misinterpret something Nico does as a threat to his friends. Thalia, being Percy's friend, jumps in to defend him. Nico, feeling attacked unjustly, then retaliates. It could turn into a full - on fight with them using their powers. Percy with his water - based powers, Thalia with her lightning, and Nico with his control over the dead. The fight could be a very intense and action - packed scene in the fanfic.
Another reason could be different loyalties. Thalia has her own group of friends and allies, and Percy has his. There could be a situation where their friends' actions or needs put them at odds with each other. For example, if Percy's friends get into trouble with something related to Thalia's friends' territory or interests, it could spark a fight.
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.
One possible cause could be a misunderstanding. Maybe Thalia misinterprets Percy's actions as being too reckless and putting their mission or friends in danger. For example, if Percy decides to take on a powerful monster alone without consulting the group, Thalia, being a protective and cautious person, might see this as a threat to the team's safety and get into a fight with him.
They could fight due to a prophecy. If there's a prophecy that involves one of them being the 'chosen one' and the others think they should be, it would create a lot of tension. For instance, if the prophecy says that only one of them can save the world from a certain doom. Percy, being the main character in many stories, might be assumed by the others to be the one, but Thalia and Nico may believe they have just as much right. Their struggle for that role could lead to a fight. And during the fight, they would use their unique abilities. Percy would call upon the water, Thalia would summon her lightning bolts, and Nico would raise the dead to fight on his behalf.
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.