Annabeth could be a main character. She might be trying to stop Percy from wanting to die. She could use her intelligence and her deep understanding of Percy to figure out what's wrong and try to talk him out of it. For example, she could remind him of all the good things they've been through together and all the people who need him.
Grover could also be a key character. Grover has always been Percy's loyal friend. He could be on a quest to find a magical cure or a way to cheer Percy up. Maybe he brings in some of his nature - related magic to show Percy the beauty of life again. Grover might also be the one who first notices Percy's suicidal thoughts and tries to get help from others.
Another possible main character could be a rival. A person who is always competing with Percy and who might use the discovery of her secret as a weapon against her. This would add a lot of conflict to the story.
There could be a strict but kind music teacher. This teacher sees Percy's potential and pushes him to practice harder and improve his skills. Another character could be Percy's best friend who is always there to support him during his musical journey, even when things get tough.
There could be an old Alaskan native who becomes Percy's guide. He has a wealth of knowledge about the land and its spirits. He helps Percy understand the ways of the Alaskan wilderness.
Jason is likely to be another main character. Since he has his own set of skills and knowledge, he might have an interesting relationship with Percy in this story. Maybe he's a bit jealous at first of Percy's control over the ship, but then they end up working together really well. And of course, Piper could be there too. She might use her charm - speak abilities to help the crew communicate with any strange creatures they encounter during Percy's time controlling the Argo 2.
There could be his best friend Grover. Grover might try to find Percy after he runs away, adding an element of search and rescue to the story.
Grover could also be a main character. He could use his nature - related abilities to assist Percy when he wields the Blades of Chaos. For instance, he might be able to sense danger in the environment that Percy can then use the blades to face. Grover could also help Percy find his way in places where the Blades of Chaos' power might be affected by the surrounding nature.
There could be other non - human characters like a wise old wizard who knows about Percy's true nature and tries to guide him. Maybe a shape - shifter who at first seems like an enemy but later becomes an ally.
There could be a wise old monster who acts as Percy's mentor. Maybe a female monster who becomes Percy's love interest. And of course, there would likely be some villainous monsters who oppose Percy's new existence and try to harm him.
Grover can also be quite prominent. His loyalty to Percy remains a key factor. In some fanfictions, his connection to nature might be enhanced to better support Percy in his overpowered adventures. For example, he could be able to communicate with more powerful nature spirits to assist Percy in battles or quests.
Well, Percy is the main character who asks to die. In addition to his friends, there could be antagonists in the fanfiction that have pushed Percy to this extreme. These antagonists could be new characters created by the fanfiction author, or they could be some powerful villains from the original series who have become even more menacing in this fan - made story.