A really interesting main character could be a former enemy turned ally. For example, a monster that was once loyal to Kronos but then had a change of heart and was cursed with the ability to shift into different monsters as a punishment. Now, they are trying to redeem themselves by helping the demigods, but they face a lot of distrust from both sides.
It could be a new character, a half - blood who discovers they have the ability to shift into monsters. This character could have a troubled past, maybe they were abandoned as a child because of their strange power. They then have to learn to control it and find their place in the world of demigods.
The main character could also be a long - lost relative of Percy. They have the monster - shifting ability, which has been hidden in their family for generations. When they discover this power, they are thrust into the dangerous world of Percy Jackson. They must rely on their wits and newfound power to survive and protect their family, all while dealing with the fact that they are different from other demigods.
A character who was a villain in their past life but is reborn with a chance to change. They would struggle with their old instincts and the expectations of others, but could grow into a hero. This kind of character arc would be really engaging as they fight against their own nature and the prejudices of the demigod community.
A cool plot might be that the monster shifter has the ability to combine the powers of different monsters when they shift. So, for example, they could shift into a creature that has the speed of a hellhound and the strength of a minotaur. This new power could attract the attention of powerful gods who either want to use the shifter for their own purposes or destroy them out of fear. The shifter then has to navigate the complex world of Percy Jackson, making allies and enemies along the way.
It depends on the specific fanfic, but often it could include Naruto - like characters who have the shifter ability. Maybe Naruto himself could be a shifter in some versions, or new original characters created specifically for the fanfic.
Maybe one of the primordial deities, like Gaea, could be the main character. The fanfic could explore her thoughts and actions as she was one of the first beings. It could show how her relationship with other primordial deities influenced the future of the universe, and how her actions in the beginning set the path for events that would unfold much later in the Percy Jackson series.
A shy and overlooked demigod would be a great choice. This character could be someone who doesn't fit in with the more battle - ready or flashy cabins like Ares or Apollo. They find their place in Hestia's cabin and gradually become more confident as they embrace the values of the cabin.
Some of the antagonist characters in Percy Jackson Monster Shifter fanfiction are also popular. For example, a rogue monster shifter who uses their powers for evil. They might be in league with the Titans or some other dark force in the Percy Jackson world. Their actions create conflict and drive the plot forward. Also, characters that are hybrids of different monsters in their shifted form are often popular. They have strange and interesting combinations of powers that make them stand out, like a combination of a griffin and a manticore.
The main antagonist could be a powerful sorcerer who has found a way to enter the Percy Jackson game world. He has his own motives, perhaps he wants to steal the powers of the demigods for himself. He's able to manipulate the game's code to his advantage, creating illusions and false paths for Percy and his friends to follow. Or it could be an ancient spirit that was sealed away in the game but has been released. This spirit is angry at the gods and demigods and wants to destroy everything they hold dear. Also, a group of bandit demigods could be the main antagonists. They don't follow the rules of the game or the real - world demigod society and are causing chaos everywhere they go, trying to steal valuable items from both the game world and the real - world locations.
Nyx could be a great main antagonist. She's a primordial goddess of the night and Tartarus is her domain in a way. She might see Percy and his friends as intruders and try to stop them from leaving or achieving their goals. She could use her power over darkness and the unknown to create all sorts of obstacles for them.
It could be a new, powerful Titan that has emerged from the depths of Tartarus. This Titan might be seeking revenge on the demigods for imprisoning the other Titans and sees Hylla and Percy as the biggest threats.
The main villain could be a power - hungry Atlantean sorcerer who wants to use the power of Atlantis to rule both the underwater world and the surface. He might see Percy as a threat to his plans and try to eliminate him.