Well, it depends on the specific fanfiction. There are countless fanfictions out there, and some authors might choose to reimagine Percy Jackson as a demon for the sake of a unique and edgy story. But the traditional view of Percy is that of a demigod with his own set of powers and adventures that have nothing to do with being a demon.
The demon lord in Percy Jackson fanfiction often serves as a powerful and menacing antagonist. They usually possess extraordinary powers that pose a great threat to the demigods in the story. For example, they might have control over dark magic or be able to summon hordes of monstrous creatures.
His relationship with Annabeth could be strained. She might be initially afraid of the changes in Percy due to his demon half. However, over time, as she sees that he's still the same Percy at heart, they could work through it and their relationship could become even stronger as they face this new challenge together.
One possibility could be that Percy, as a demon, struggles with his new identity. He might have to deal with new powers that are difficult to control. For example, he could accidentally harm his friends. He may also face discrimination from those who fear demons, even though he's still the same person deep down.
One of the main themes in 'percy is half demon fanfic' is the battle between good and evil within Percy. Since he is half - demon, he has that dark side, but he also has a good side. There's also the theme of isolation. He might feel alone because of his unique nature. And finally, the theme of discovery, as he discovers more about his demon heritage and what it means for him.
Well, a lot of them deal with the idea of forbidden knowledge. The demons might possess knowledge that Percy is tempted to seek, but it's dangerous. Also, there's often the theme of redemption. Some fanfictions might have a demon character that Percy tries to redeem, or a situation where Percy himself has to be redeemed after getting involved with the demons in some way. There can also be the theme of identity crisis, as Percy might question who he is when faced with the allure of the demonic world.
Yes, there are. You can find some on fanfiction websites like Archive of Our Own. Some might explore Percy having to face demon - like creatures in a new and unique way, perhaps in an alternate universe where the rules of the Percy Jackson world are slightly twisted to include more demonic elements.
One common theme is the struggle between good and evil. Since demons are often associated with evil in the context of these fanfictions, Percy has to decide how to deal with them. Another theme is power. Percy may gain new powers related to demons or have to face the overpowering force of demons.
One reason could be for a fresh take on the story. Writers might want to break away from the typical demigod narrative and explore a darker, more supernatural side of the Percy Jackson universe. Another reason could be to create a more complex and morally ambiguous character. By making him a demon, they can introduce new conflicts and relationships.
Percy is the central figure. In addition to him, there could be antagonists. For example, other demon lords who see Percy as a threat to their power. And there might be characters who act as mentors or guides for Percy, even if they are demons themselves. They could help him understand the ways of the demon world. Also, there could be characters from Percy's human world who end up in the demon realm and Percy has to decide how to deal with them.