The main character is Percy, no doubt. However, in this type of fanfiction, we could also expect to see characters like Thalia Grace. She has her own connection to Percy and could offer a different perspective on his situation. The centaur Chiron might also be a main character as he is often a guiding figure for the demigods. And there could be new characters introduced, perhaps other dark - themed characters who are either drawn to Percy or are trying to oppose him because of his changed state.
Obviously, Percy would be the main character. He's the one stuck in Tartarus, so the story would revolve around him. Maybe Annabeth could also be an important character, even if she's not physically in Tartarus with him. Her thoughts and attempts to rescue Percy from afar could be part of the story.
Obviously, Percy is one of the main characters. Given the 'dark' aspect, he may have a more brooding and conflicted personality compared to his normal self.
Obviously, Percy would be the main character. Since he is the one sent to Tartarus. Annabeth might also play an important role, even if she's not in Tartarus with him at first. She could be on the surface world trying to figure out a way to get to him or send help. Grover could be another likely character. His connection to nature might come in handy in some way, like if there are strange nature - based elements in Tartarus that only he can understand or control.
Obviously Percy himself. Annabeth would likely be there as she has a close relationship with Percy. Grover might also show up, being Percy's long - time friend. And some of the other demigods from Camp Half - Blood, like Jason or Piper, could be in the story too.
Well, Percy himself is of course the main character. Annabeth would also be very likely to be there. Their relationship is a big part of the Percy Jackson series, and in a Tartarus - related fanfiction, she could be either with Percy from the start or trying to find a way to rescue him. Grover might also show up. His loyalty to Percy and his skills as a satyr could be useful in the dangerous environment of Tartarus.
Annabeth might also be a main character. She could be either with Percy in Tartarus or be a driving force for him from outside, like trying to find a way to rescue him or communicate with him in some way.
Obviously, Percy would be one of the main characters. Since it's about him training in Tartarus. And Annabeth might also be involved. Maybe she's helping him in some way, or she's waiting for him outside Tartarus while he trains.
Obviously, Percy is one of the main characters. Since he's the one sent to Tartarus. There might also be some of his old friends who play important roles, like Annabeth. Maybe she's on a quest to save him, so she becomes a central figure in the fanfiction.
Annabeth is a very likely ally. Their relationship is so strong that she would follow him into Tartarus and be by his side through thick and thin. Grover could also be an ally. He's Percy's long - time friend and his skills as a satyr could come in handy in Tartarus. Nico di Angelo is another possibility. His knowledge of the Underworld and his powers over the dead could be useful in the dangerous Tartarus environment.
In some more creative fanfictions, new characters might be introduced. For example, a powerful demigod who was born in Tartarus and has unique abilities. These new characters can add a fresh twist to the story, interacting with Percy and the others in unexpected ways, and often bringing new plotlines related to the mysteries of Tartarus.