Perhaps it's a cultural or family - related thing in the fanfiction. Maybe in Percy's family or the culture he was raised in, men were seen as unpredictable or dangerous. His mother might have instilled this fear in him unconsciously, or there could have been a family history of bad experiences with men that influenced his view.
One possible reason could be past trauma. Maybe he had a bad encounter with a man in the past, like a bully or an authority figure who mistreated him. This could have left a deep scar, making him terrified.
Another way is to explore his internal thoughts and feelings. By delving deep into why he's terrified, the author can show Percy's vulnerability and also his strength as he tries to deal with this fear. This could involve flashbacks to past experiences that shaped his fear, and how he copes with them in the present in the fanfiction.
It might also be related to some sort of enemy or threat that specifically targets Percy and his relationship with Annabeth. The enemy could be so powerful that Percy realizes the only way to stop it from harming Annabeth is to sacrifice himself, like if the enemy feeds on his life force or his connection to Annabeth, and he chooses to end it by sacrificing his own life.
Maybe he faced an extremely powerful enemy that he couldn't overcome. It could be a new and terrifying monster created by the Titans or some other dark force.
Some fanfiction writers may do it to stand out. Since the Percy Jackson series is so well - known, creating a version where he is a devil can attract attention. Also, it could be a way to explore darker themes. The original series has a lot of heroic and positive elements, but in fanfiction, making Percy a devil allows for a look at the other side of the coin, like how his powers could be used for evil instead of good.
One possible reason could be that Percy has shown some extraordinary power that even Thor, a powerful god, respects. Maybe Percy has defeated a common enemy in a really remarkable way that makes Thor recognize his strength and kneel in admiration.
Maybe Percy unknowingly breaks some ancient and very strict laws of the Gods. For example, he might interfere with some sacred rituals or places that are off - limits to mortals, even demigods like him. In the fanfiction world, the Gods could be very unforgiving when it comes to such violations and decide to kill him as a result.
Perhaps Percy has proven his worth through his unwavering loyalty and courage. Loki, who is used to seeing self - serving and deceitful behavior among the gods and mortals, is impressed by Percy's pure - heartedness. His actions of always protecting his friends and standing up for what is right might make Loki feel that he is worthy of respect, leading to Loki bowing to him.
There are several possible reasons. Firstly, for the sake of drama. It makes for a very intense and emotional story when a beloved character like Percy dies. Secondly, it could be to explore the after - effects on the other characters. How would Annabeth cope? How would the Camp Half - Blood react? Also, it might be a way to show the unforgiving nature of Tartarus.
Well, in fanfiction, one reason could be the loss of his friends. Percy has been through so many battles, and if he loses someone close like Annabeth or Grover, it could send him into a deep depression. Another reason might be the burden of his prophecies. He's constantly expected to save the world, and that kind of pressure can wear a person down over time.
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.