His perception of time would be different. As a primordial, Percy could move freely through time, seeing the past, present, and future all at once. This would give him an advantage in decision - making. His friends like Annabeth might not be able to understand him as well as before. He would be on a different plane of existence, and his concerns would be more about the stability of the cosmos rather than the problems within the demigod community. He could also have new allies, primordial beings from other mythologies, and together they could shape the multiverse.
In fanfiction, if Percy Jackson becomes a primordial, it would be a huge shift in the narrative. He could be involved in the creation or destruction of new worlds. His personality might also change. He could become more detached, like many primordial beings are, as he now views the world from a much higher and more complex perspective. He might have to make decisions that affect the entire fabric of existence, and his actions would have consequences on a universal scale.
His life would change drastically. He would be a being of immense power. He would no longer have to fear the wrath of the Olympians as he would be on a similar or even higher level. He could shape the world as he wished.
If Percy becomes a werewolf in fanfiction, his social life would be turned upside down. His friends at Camp Half - Blood might be hesitant to be around him, fearing his new, more unpredictable nature. He might be drawn to other werewolves or creatures of the night, which could introduce him to a whole new set of allies and enemies. Also, his training as a demigod would need to be adjusted to account for his werewolf abilities, like learning to fight in his new form without losing control.
His character might become more aloof. As a primordial god, he would be far removed from the normal world of demigods. He'd likely have a different perspective on things like friendship and loyalty. For example, he might not be as quick to jump into a fight for his friends as he used to be, because his new status would bring a different set of responsibilities.
Percy's character would evolve into a more solitary figure. As Chaos, he'd be in a realm where few can understand him. He might struggle with loneliness, yet at the same time, he'd be filled with a sense of purpose that is much grander than his previous quests. His loyalty would shift from his friends on Earth to the well - being of the entire universe.
The plot of the story would take a whole new turn. Percy would likely be involved in different quests. Instead of quests related to saving the world from Titans or Giants, he could be involved in Underworld - related problems like stopping a rebellion among the dead or dealing with power struggles within the Underworld itself. His allies would also be different. He might team up with Underworld creatures like the Furies or the ghosts of powerful heroes instead of the demigods from Camp Half - Blood.
Percy's character would be much more of a warrior. In Sparta, they were bred for war. Percy would have a different mindset. He'd be more aggressive in combat and less hesitant to use force. His sense of honor would be deeply ingrained in the Spartan way. He'd also be more used to a hierarchical society, so his interactions with others might be more formal. For example, he'd show more respect to his superiors based on their rank. His relationship with the gods would also be different. He'd have to hide his connection to Poseidon more carefully as the Spartans had their own pantheon of gods they revered, and any deviation from that could be seen as heresy.
If Percy Jackson becomes a god in a crossover fanfiction, his character would experience a significant transformation. He has always been a hero who fought for the underdog. But as a god, he might have to make difficult decisions that could go against his old principles. His view of right and wrong could become more nuanced. He would also have to deal with the envy and fear of those around him. His mortality - which was a big part of his identity - would be gone, and he'd have to redefine himself in the context of immortality. His sense of time would change, and he might start seeing things from a much longer - term perspective. All these changes would make his character much more complex and different from the Percy we knew as a demigod.
He might become more war - like. Norse gods are often associated with battle, so Percy could lose some of his more laid - back Greek side.
His sense of humor might change. He could become more wry and god - like in his jokes. Also, he might be more decisive, as a god has to make big decisions quickly. However, his love for his friends and family would still be there, just expressed in a different way perhaps, more like a distant protector.