Gods and demigods' reactions would likely vary greatly. Those with a sense of humor might find the fanfiction hilarious and embrace the creativity. However, more prideful ones could be outraged. They may view fanfiction as a form of disrespect to their divine status. And then there are those who might be indifferent. They simply don't care what mortals write about them in fanfiction as long as it doesn't directly interfere with their divine affairs.
They might react with surprise. Fanfiction often has very different takes on their characters and stories.
They could be amused. It's like seeing a mirror of their world but with a school - based twist. They might like the creativity behind it.
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.
Some gods might be entertained. For instance, Hermes, being the trickster god, might enjoy seeing the different and often humorous takes on the gods in the fanfiction.
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.
If gods and demigods read fanfiction, they might be amused. Some might find the creative interpretations of their stories and characters quite interesting. They could also get angry if the fanfiction distorts their image in a way they don't like.
Naruto's reaction would vary greatly. For stories that show his growth in new and interesting ways, he could be inspired. He might think about how he could apply some of the ideas in his real ninja training. But if there are fanfictions that are too far - fetched, he might scratch his head and wonder what the author was thinking. And if there are ones that play with his emotions in a way that's too intense, he might need some time to process it all.
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.
Initially, Naruto would be heartbroken. His friends and his village mean everything to him, and the thought that the gods, who are supposed to be just, have turned against him would be a huge blow. However, he wouldn't give up. He would use his determination and his unwavering belief in himself. He might start looking for allies among those who are also disillusioned with the gods or who believe in his innocence.
Gabe would probably be very intimidated at first. Demigods have powers and abilities that are far beyond what he's used to. He might act tough at the start to hide his fear, but as he sees more of what they can do, he could become more submissive or try to make friends with them out of self - preservation.
They would probably be shocked. Demigods have extraordinary abilities, like being able to control water or run super fast. Percy's mortal friends, who are used to a normal world, would be taken aback by such powers.