Athena is Annabeth's mother. Although she generally has some level of trust in Annabeth, she might still spy on them. She could be worried about how Percy's actions might influence Annabeth, especially when it comes to decisions that could affect their future or the future of the demigods. Also, she might want to ensure that Annabeth doesn't let her emotions for Percy cloud her judgment.
Aphrodite could also be one of the spying gods. Since she loves meddling in love affairs, and Percy and Annabeth's relationship is quite famous among the demigods. She might be spying to see how their relationship develops and perhaps add a little nudge here and there if she feels like it.
One possibility is that the gods are spying because they fear Percy and Annabeth might be planning something that could disrupt the balance between the mortal and divine worlds. For example, they could be working on a project that might give mortals too much power over the gods, so the gods want to keep an eye on them to stop it if necessary. Also, it could be that the gods are just being nosy as they are often interested in the affairs of their favorite demigods.
Obviously, Percy would be one of the main characters. And the gods who are spying on him, such as Zeus, Poseidon, or Athena, would also be main characters. They play important roles in the spying plot.
I think 'the gods spy on percy fanfiction' would likely involve the gods using their various powers to keep an eye on Percy. They could be using magic, or enlisting the help of other mythical creatures. This fanfiction might also show how Percy's friends get involved when they discover the spying, and the resulting conflicts or alliances.
Poseidon would probably be one of the main gods watching. Since Percy is his son, he would have a strong interest in his well - being during the fight.
In some fanfictions, if Percy and Annabeth became gods, they might bring new powers and perspectives to Olympus. Percy could use his water - controlling abilities in more divine ways, like creating entire new oceans or taming sea monsters on a grander scale. Annabeth, with her wisdom, could reshape the way the gods make decisions, bringing more logic and strategy to their councils.
One possible fanfic could be where Percy and Annabeth are faced with a fate that the gods have secretly planned for them. Maybe the gods, in their eternal scheming, decide that Percy and Annabeth's love is a threat to their power. So they create a series of challenges that seem to be fated for the couple. Percy and Annabeth, being the strong - willed demigods they are, fight against this pre - ordained fate. They might journey to different realms, trying to find a way to change their fate and prove that their love can withstand even the gods' meddling.
I think Poseidon is a must - he's Percy's father, after all. Then there's Zeus, who likes to be in control and would want to see this baby who could grow to be a significant force. Apollo might come just for the fun of it, being the god of many things including prophecy, he might have some insights. And Artemis, as the goddess of the hunt, could also be there to see what all the fuss is about regarding baby Percy.
There might be some new characters introduced in the fanfiction who have different ideals or motives that clash with Annabeth's. These new characters could be the antagonists as they oppose Annabeth, and Percy has to step in. For example, if they think Annabeth's way of handling a certain quest is wrong and Percy believes in her, he'll fight against their ideas.
The gorgons could be a likely villain. They might be lurking in the catacombs of Paris, waiting to turn Percy and Annabeth into stone. They could be after some powerful magic item that is hidden in the city.
Probably Poseidon, as he is Percy's father and has a vested interest in his son's well - being. Zeus might also be protective in some cases, despite their past differences, as Percy is a hero who often saves the world which benefits Zeus's realm as well.