Who could be the main antagonists in a 'Percy back in time fanfic'?

The main antagonists could be the original Naruto's friends and allies. Since this is an evil Naruto, people like Sasuke, Sakura, and Kakashi would likely oppose him and try to stop him from whatever evil plans he has in the past.

In this kind of fanfiction, the Titans could also be antagonists. They might want to use Percy's power over time to their advantage. Maybe they think they can rewrite history in a way that would bring them back to power. Kronos, in particular, if he were somehow still a threat, could be a major adversary. He could try to manipulate Percy into using his time powers in a way that would benefit the Titans, like going back and changing events that led to their downfall.

The Titans could still be antagonists. In the Percy Jackson universe, they are powerful and malevolent. A princess in a fanfic might have to face their wrath as they try to overthrow the gods and take over the world. They would see the princess as a threat, especially if she is allied with the gods or has some special power that could stop them.

The Titans could still be antagonists. Since Percy has a connection to Hecate, they might see him as a threat to their plans of overthrowing the gods. They could try to capture him to use his powers for their own evil purposes.

Another possible antagonist could be some of the Hogwarts faculty who were either secretly supporting Voldemort or were too cowardly to oppose him. In a time - travel revenge fanfic, Harry might uncover their true natures and take revenge on them for not doing more to protect the students and the wizarding world from Voldemort's rise.

Even some of the ancient demigods who turned bad could be antagonists. They might see Percy as a threat to their power or plans in the past. They could have different values and goals compared to Percy, leading to conflicts. For example, a demigod who was power - hungry and wanted to use time - travel to change things for his own gain, and Percy would have to stop him.

The other gods might be antagonists. For example, Zeus could be against Artemis getting Percy back because he doesn't trust Percy or he has his own plans for Percy that don't align with Artemis'. Another god like Ares could also be an antagonist as he might see Percy as a threat and not want him to be on Artemis' side.

The Titans could be great antagonists. They might see Percy as a threat because of his connection to Thanatos and the power it could potentially give him. Also, some rogue underworld creatures, like powerful demons or vengeful spirits, could oppose Percy. They may not want Thanatos to have a more powerful influence through Percy.

Some of the more powerful and vengeful spirits in the Underworld itself could be antagonists. They might not want an outsider like Percy to be the Champion of Hades. They could try to undermine him at every turn, like spreading false rumors about him among the other Underworld denizens or directly attacking him when he's vulnerable during his quests in the Underworld.

Some of the primordial gods who are jealous of Chaos's newfound relationship with Percy could be antagonists. They might view Percy as an upstart and try to undermine his position. For example, Erebus could try to create chaos in Percy's life in a more malicious way, not in the way that Chaos intends.