Some gods might be neutral. They would be more concerned with how this event would disrupt the balance of power among the gods. They might try to negotiate or find a compromise to avoid further bloodshed and chaos in the world of the gods.
The other gods would probably be very cautious around Percy. Since he's Zeus' younger brother, they would fear that any wrong move towards Percy could anger Zeus. For example, Poseidon might be more respectful towards Percy than he would be to an ordinary demigod, as he wouldn't want to create a rift with Zeus over Percy.
On the other hand, Percy could become more of a revolutionary figure. His act of killing Zeus could inspire other demigods to stand up against the unjust ways of the gods, and Percy would have to step into a leadership role, which would force him to grow in terms of strategy and diplomacy.
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.
It could also be about power. Percy might realize that with Zeus out of the way, he can reshape the world of the gods in a more just and fair way. He could believe that Zeus's rule is corrupt and that killing him is the only way to bring about real change.
The gods' reactions would also depend on the political climate in Olympus at the time. If there was already tension between different factions, this incident could be the spark that ignites a larger conflict. For example, if the nature - loving gods were at odds with the more war - like gods, Percy's situation could be used as a tool. Artemis, being a powerful and independent goddess, would have to navigate through all these political undercurrents while trying to make amends for her mistake to Percy.
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.
Sasuke would likely be filled with rage. He and Naruto had a complex relationship, and Naruto's death at Sakura's hands would make Sasuke seek revenge or at least demand answers. Kakashi, on the other hand, would be deeply saddened. He was Naruto's teacher and would probably feel a sense of failure.
She might be grateful. After all, if she has a fear or aversion to spiders, Percy getting rid of it is a kind gesture.
At first, Percy might be hesitant and conflicted about killing the gods. He's always had a complex relationship with them. But as he's pushed further into the situation, he could become more hardened. Maybe he starts to see the gods as truly corrupt and that killing them is the only way to save the world. This would make him more decisive and perhaps a bit more ruthless.
At first, Percy could be in shock. He can't believe that the gods, whom he has served and trusted, would betray him. But then, as the reality sinks in, he might become determined to get justice. He starts to plan his next moves carefully, using his wits and the skills he has learned over the years. He may also feel a sense of sadness and loneliness, as he realizes he is now on his own against the powerful gods.