An interesting concept for a Percy Jackson God OC fanfiction could be an OC who was created by the gods as an experiment. This OC would have powers that are a combination of different gods' powers, but they are also an outcast among both gods and demigods because of their origin. They might struggle to find their place in the world and go on a journey to discover who they really are and what their purpose is. Along the way, they could form unlikely alliances with both demigods and minor gods who also feel like outsiders.
Another interesting concept is an SI OC who is from a different time period, like the Middle Ages. They would have to adapt to the modern world of Percy Jackson while also using their archaic knowledge and skills to their advantage. Maybe they know ancient battle tactics that are useful against the Titans or Giants. They could also introduce medieval weaponry and fighting styles to Camp Half - Blood.
Another plot could involve an OC who is a child of a minor god that has been overlooked by the Camp Half - Blood community. This OC, with Percy's help, tries to prove the importance of their godly heritage and ends up uncovering a long - lost prophecy related to their parent god. This would lead to an adventure full of self - discovery and challenges for both the OC and Percy.
One idea could be an OC with the power to control water in unique ways, like creating ice sculptures that can come to life. Another could be an OC who has the magic to communicate with mythical animals and use them as allies. Maybe an OC with magic that allows them to manipulate time on a small scale, like freezing time for a few seconds during a battle.
In fanfiction, Percy might discover a hidden connection between his powers and the archangel's. Maybe there's a prophecy that links them, and they have to figure out how to fulfill it together. The archangel could teach Percy some new skills or perspectives that are different from what he's learned in the demigod world.
One idea could be exploring how Percy discovers he has a connection to the first god that no one else knows about. Maybe he has strange dreams that lead him on a quest to uncover the secrets of this primordial deity.
One idea could be that the OC is a new camper at Camp Half - Blood. She has a special power that Percy is intrigued by. They start off as friends, helping each other in various quests. As time goes on, they realize their feelings for each other during a particularly dangerous quest where they have to rely on each other completely.
Well, perhaps in the fanfiction, the Angel of God is a messenger to Percy, warning him of a great catastrophe that will befall the demigod world. Percy then has to gather all the demigods and prepare them for this threat. The angel could also have the power to bestow temporary divine abilities on Percy and his friends, which they use to battle an army of dark creatures. Or it could be that the angel is actually a lost soul from a previous era, and Percy has to solve the mystery of its past to get its help in saving his world.
One idea could be that the Evil God manipulates Percy's friends against him. For example, making Annabeth doubt Percy's loyalty through false visions. Another could be that the Evil God corrupts the demigod world's magic, turning it against the heroes. Maybe the water Percy usually controls starts to harm him instead of help.
Maybe Percy is chosen by the Fates to be their champion in a battle against an ancient evil that threatens to disrupt the very fabric of fate. He has to team up with some unlikely allies, like minor gods who are also concerned about the balance of fate. He would have to learn new skills and face challenges that test his limits.
One idea could be Percy having to face a new and powerful monster that is a combination of multiple mythological creatures. This would test his skills and force him to come up with new battle strategies.