Well, in this kind of fanfic, perhaps Percy is disowned due to false accusations. For example, he might be wrongly blamed for a major incident at Camp Half - Blood, like a destructive event that was actually caused by an enemy's trick. As a result, the camp leaders or his friends' families decide to disown him. He then has to struggle to prove his innocence while being on his own.
One possible scenario could be Percy being disowned because of his powers being seen as too dangerous. Maybe the other demigods or even his own family in the fanfic fear what he can do and decide to cut ties.
It could be a jealous demigod. Maybe someone who has always been envious of Percy's popularity and power. This demigod could spread lies about Percy that lead to his disownment, making them the main antagonist.
In a 'Percy Jackson Dies' fanfic, one possible scenario could be that he sacrifices himself to save his friends during an epic battle against a powerful new enemy. Maybe a horde of monsters that are immune to his usual powers overwhelm him while he's trying to buy time for his friends to escape.
It could be that Percy's relationship with a certain god or goddess goes horribly wrong. Say he offends Aphrodite in a way that she convinces the other gods to disown him. Percy then has to struggle not only with the loss of his divine family but also with the isolation from the demigod community that follows such a disownment.
One possible plotline could be that Sally is disowned by her family for being involved with the world of the gods. Percy then has to go on a journey to find a way to restore her family's acceptance. He might face various mythological creatures and challenges along the way. Another idea could be that Sally's disownment is part of a plot by an enemy to get to Percy. So Percy has to protect his mother and also figure out who is behind this scheme. It could also be that Sally discovers a dark secret about her family that leads to her being disowned, and Percy helps her uncover the truth and clear her name.
Well, one scenario could be that Percy is bullied in school. Maybe the bullies pick on him for being different, like if he has some unique abilities or is just not as popular. Another situation could be that he's bullied in a new environment, like a summer camp, where the other kids don't accept him at first. It could also be that the bullies target Percy because of his family background or something that makes him stand out in a way they don't like.
There could be a rival within the family. Someone who wants Percy out of the way, perhaps for inheritance reasons or because they're jealous of Percy's abilities or popularity. This rival could be the one who instigates the events that lead to Percy's disownment. And then there might be a mentor - like figure outside of the family who takes Percy in after he's disowned and helps him to grow and face his new situation.
Well, I'm not sure of the exact titles, but a good 'Percy Jackson disowned' fanfic would probably explore Percy's emotions deeply. It could show him feeling betrayed by his friends and the gods. Maybe it would have him going on a solo adventure to prove his worth. He might encounter new allies and enemies in the process. It could also be interesting if the fanfic explored how the other demigods reacted to his disownment, whether they supported him or not.
One possible plot twist could be that Triton is not actually there to help Percy but is being controlled by an enemy to spy on him. So, Percy might think he has a new ally but in fact, he is being set up.
One common scenario is when another girl shows interest in Percy. For example, if a new demigod arrives at Camp Half - Blood and she's constantly around Percy, Annabeth might get jealous. She could start acting cold towards Percy or be overly critical of the new girl. Another situation could be if Percy has to go on a quest with a female partner and they seem to be getting along really well. Annabeth might worry that Percy will develop feelings for this other girl.
One possible scenario could be that Percy has faced so many traumas and losses in his battles against the monsters and gods' schemes that he simply feels exhausted and wants an end. For example, if he loses his close friends like Annabeth in a particularly brutal way, it might push him to the edge.