It could be an ancient deity that was banished long ago. Maybe a primordial god or goddess who was considered too powerful or too dangerous for the other Olympians. For example, it could be Erebus, the god of darkness.
Well, it could be about Percy facing a new and powerful threat that even the Olympians can't handle easily. Maybe he discovers a hidden 13th Olympian who has been locked away for centuries and now is causing chaos.
Well, you could write a fanfiction where Percy loses his memory and has to rediscover his powers and his place among the demigods. Or perhaps a story about how the minor gods in the Percy Jackson universe form their own alliance because they feel overlooked by the Olympians. You could also create a fanfic that focuses on Annabeth's journey if she was separated from Percy and had to fend for herself in a dangerous situation.
In this fanfiction, it could be that Percy is chosen for a special task by the existing Olympians. They see his potential not just as a hero but as someone who could join their ranks. So he gets trained in Olympian magic and lore, which is very different from what he's used to. He has to learn how to control new powers and also deal with the politics among the Olympians.
The other characters would be devastated. Annabeth, for instance, would be heartbroken. She has been through so much with Percy, and his death would leave a huge void in her life. She might become more withdrawn and less trusting. Grover would also be deeply affected. He has been Percy's friend since the beginning, and he would probably blame himself for not being able to protect Percy. The other demigods would lose their hero, and they might feel less confident in their ability to defend Olympus.
Fanfiction based on 'Percy Jackson: The Last Olympian' can be quite diverse. Some might focus on the relationships between the characters, like Percy and Annabeth's relationship evolving in new ways. Others could explore the idea of new threats emerging in the demigod world. It's also a great way for fans to connect with each other, sharing their ideas and interpretations of the story.
In the 'Percy Jackson Last Olympian Graphic Novel', Percy Jackson is the central figure. He is the hero of the story, constantly facing challenges and growing. Annabeth, his friend and love interest in a way, is a crucial character. Her knowledge of architecture and strategy is invaluable. Grover, with his connection to nature as a satyr, provides both comic relief and support. Then there are the gods, whose power struggles and politics form the backdrop of the story. Each character, whether demigod or god, has their own motives and personalities, which all come together to create the complex and exciting world of the graphic novel.