In this fanfiction, apart from the obvious choice of the gods as antagonists, there could also be some of their loyal servants. For example, the Cyclopes who are known to be strong and often do the bidding of the gods. They could be sent to hunt Percy down. Also, some of the more powerful demigods who are on the side of the gods out of fear or loyalty might also oppose Percy and try to capture him.
The main antagonists would most likely be the gods themselves. Since the title mentions being hunted by the gods, they would be the ones sending various threats Percy's way. It could be Zeus, who is often quick to anger and punish those he thinks are a threat to his power.
It could also be that the Olympian Council as a whole acts as the antagonist. They might have made decisions that Percy sees as a betrayal, such as sacrificing the safety of demigods for their own political gain. Each god on the council, with their own self - interests, might contribute to Percy's feeling of betrayal, making the council as a whole the main force he has to oppose.
The traditional gods who don't want to see Percy as king could be antagonists. For example, Zeus might see Percy as a threat to his power and try to stop him at every turn.
One possible plot could be that Percy has somehow angered the gods, perhaps by accidentally disrupting a major ceremony. As a result, they send various mythical creatures to hunt him down. He has to use his wits and demigod powers to outsmart them and find a way to make amends with the gods.
Other jealous demigods could act as antagonists. They might feel that Percy doesn't deserve the blessings and try to undermine him. They could spread rumors or even try to sabotage his quests to make him look bad in the eyes of the gods.
The Giants might also be antagonists. They could band together and target Percy's kingdom, believing that by destroying him and his rule, they can undermine the power of the gods further. They might use their brute strength and strategic thinking to attack Percy from different fronts.
Another option could be a group of rogue demigods who have turned to the dark side. They follow Percy to Forks, hoping to find some powerful artifacts there. They don't care about the vampires or werewolves and are willing to cause destruction to get what they want. Percy has to stop them while also dealing with the local supernatural creatures.
Well, in the 'Percy Jackson hunted by Shield' fanfiction, Percy's main source of help would be his demigod comrades. Annabeth Chase, with her brilliant mind and knowledge of architecture and strategy, could help Percy plan his escapes and defenses. Grover Underwood, being a satyr, has a connection with nature that could be used to create barriers or mislead Shield's agents. Additionally, Chiron, the centaur trainer at Camp Half - Blood, might have some ancient knowledge or magic that could be used to protect Percy or make him less detectable to Shield. There could also be other demigods with unique powers that could come to Percy's aid, for example, those with the power of invisibility or mind - control who could use their abilities to disrupt Shield's operations.
The Titans could be the main antagonists. Even though they have been defeated before, some of them might have found a way to return or their followers could be causing trouble. They see Artemis as a threat or a target for their revenge against the gods. Another possibility is a new group of powerful monsters that have banded together and are specifically targeting Artemis for her power and influence among the demigods.
Well, the main antagonists could be a group of rogue demigods who have formed a cult around Kronos. They believe that Percy, as the heir of Kronos, should lead them in overthrowing the current order of the demigod world. But Percy doesn't want any part of it, so they become his enemies. Another possible antagonist could be an ancient being that was once in league with Kronos and now sees Percy as a means to resurrect Kronos or continue his dark legacy. This being would stop at nothing to force Percy to embrace his role as the heir.
Perhaps some of the older, more traditional gods could be antagonists. They might see Percy as a threat because he's now the God of Dinosaurs and they fear the power he could gain from controlling these ancient and powerful creatures. For example, Zeus might be worried that Percy's new role could disrupt the existing power balance among the gods.