One of the main characters could be a human who has a special connection to the baby gods. This connection could be a mysterious prophecy or a unique power that allows them to communicate with the baby gods. The baby gods themselves, of course, would be central. And there could be a villainous character, perhaps a jealous god or a dark force that wants to use the baby gods for their own evil purposes. This villain would create conflict and drive the story as the heroes try to protect the baby gods from their clutches.
Obviously, the baby gods themselves could be main characters. Each with their own unique personalities and powers. For example, a baby god of the sea might be curious and mischievous like Poseidon. Another could be a demigod who discovers the baby gods and takes on the role of their protector. This demigod would have to deal with the challenges of protecting these powerful but inexperienced beings. And there could also be an older god who has an interest in the baby gods, either for good or bad reasons, and becomes a central figure in the story.
His mom, Sally Jackson, could be a main character. She might be the one reading the books to baby Percy at first and then be there to answer his questions as he reads on his own later.
Percy Jackson is likely still one of the main characters. After all, he's the central figure in the original series. And Annabeth might also be there, as she's always been by Percy's side.
It could be an envious demigod who feels that Percy doesn't deserve his new position as a consort of the gods. This demigod might plot against Percy, trying to undermine his influence among the gods and the other demigods.
A group of rogue demigods who have turned against the gods and see Percy as a traitor for being so close to them. They form an alliance and try to stop Percy from fulfilling any quests or tasks given to him by the gods, and might even try to capture or kill him.
Set, the Egyptian god of chaos. He could be a great antagonist as he might see the combination of Greek and Egyptian powers in Percy and the other demigods as a threat to his own plans of spreading chaos. He could try to manipulate events to turn the two groups against each other.
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 main antagonist could be one of the major gods who cursed Percy. For example, Zeus might be angry with Percy for some reason and decide to curse him. Zeus would then use his power to send all kinds of obstacles and enemies Percy's way. He could manipulate the weather to create storms that target Percy or send powerful monsters after him.
Well, Percy Jackson himself would obviously be the main character. And since it's about being a slave of the gods, gods like Zeus, Poseidon, and Athena could be important characters as well, as they might be the ones either enslaving him or having some role in his enslavement or liberation.
Another possibility is a demigod who has turned against the other demigods and sided with a particularly cruel god. This demigod could have been corrupted by power or a desire for revenge, and they use their knowledge of the demigod world to help the god in the war. Percy would then have to face this former ally, which would be a very emotional and difficult conflict for him.