Apollo would probably love it. Since he is the god of poetry and creativity, he'd be intrigued by the different interpretations of himself in fanfiction. He might even get some new inspiration for his own creative works from it.
Hades might be indifferent at first. He is often isolated in his underworld realm and not too concerned with what mortals write about him. But if he reads one that really misrepresents him as some kind of evil tyrant (more so than the usual view), he might get a bit annoyed. However, if there's a fanfiction that shows a more complex and sympathetic side of him, he could be secretly pleased.
Athena would analyze it deeply. She is the goddess of wisdom. She would study the various portrayals in fanfiction, noting the different ways mortals understand her character. She might pick out the parts that are completely off - base according to her self - perception, but also appreciate the ones that show her intelligence in new and interesting ways.
Athena, being the goddess of wisdom, might analyze the fanfiction. She could look at how the mortal writers understand the Greek mythology and use it to create new stories. She might be impressed by the intelligence and creativity of some of the fanfictions, or she might be critical of inaccuracies.
Well, some past gods might be amused. They'd see these modern interpretations of their stories and characters in the Percy Jackson fanfiction as a strange yet interesting new form of worship or at least attention. For example, Zeus might be a bit irked at some of the liberties taken with his character, but also secretly flattered that people are still so interested in him.
Most of the gods would be confused at first. Hera might see it as an opportunity to manipulate the situation for her own ends. She could try to use Percy's new connection to Ares to create more chaos or to further her own plans. Poseidon would be very conflicted. On one hand, he has a connection to Percy as his son, but now Percy has this new link to Ares which could put Poseidon in a difficult position among the other gods.
Percy's reaction would be a mix of confusion and fascination. The world of Kratos is so foreign to him, with different rules and a much darker tone. However, he would also be drawn to the hero's journey that Kratos undertakes in the fanfiction, comparing it to his own journey as a demigod.
Ruby would be excited. She loves stories full of action and adventure, and Percy Jackson fanfiction would be right up her alley. Weiss might be a bit more reserved, but could still find aspects of it to enjoy, like the complex characters. Blake would be interested in the themes of the story, such as loyalty and friendship. Yang would be enthusiastic, especially about the fight scenes and the strong characters in the fanfiction.
Bruce Banner, when he's not in Hulk mode, would be really interested in the scientific aspects that might be hidden in the Percy Jackson fanfiction. Even though it's a world of magic, he could look for ways that the magic could be related to some kind of scientific principle. He might also be interested in how the characters control their powers, whether it's Percy with his water powers or the Avengers with their various abilities, and look for similarities in self - control and management of power.
Well, in a 'Percy Jackson Gods Reveal Themselves' fanfiction, it could start with a strange event like a sudden burst of divine energy. Percy and his friends would then be in the middle of it. The gods might show their true selves to gain more control over the demigods or to seek help from them. It could also lead to a re - evaluation of the relationship between the gods and the human world.
The teachers at the school would be completely clueless. They'd be trying to regain control of the assembly, but when faced with gods, their normal disciplinary methods would be useless. One teacher might try to be brave and tell the gods to leave, only to be turned into a small, squeaking mouse by Hecate as a warning. Meanwhile, Percy and his friends would be scrambling to fix the mess before things got even worse.
He might be intrigued. After all, it's about a world he's somewhat connected to.
Percy could be a bit skeptical at first. He's been through a lot in his own world, and fanfiction might seem a bit strange to him. But as he reads more, he could get really into it. He might find himself rooting for the characters in the Red Pyramid fanfiction, especially if they remind him of his friends or himself in some way. For example, if there's a character who is an underdog but has great potential, just like Percy felt in his early days.