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.
Percy is the main character, of course. In addition, characters like Nico di Angelo could be important. Nico has a connection to the Underworld and Tartarus, so he might be able to provide some insights or even try to enter Tartarus to help Percy. Chiron, the centaur, might also be involved in some way. He could be guiding Percy's friends on the surface in their efforts to save him. And who knows, there could be some original characters created by the fanfiction author that have their own motives and powers within the context of Tartarus.
Percy is the central figure without a doubt. But in fanfiction, new characters might be introduced as well. There could be some ancient beings that Percy meets in Tartarus. Maybe a primordial deity who has been trapped there for eons and has some knowledge that Percy needs. However, his friends from Camp Half - Blood, like Tyson, could also be involved. Tyson's strength and loyalty could be factors in a plan to rescue Percy. And of course, there could be some antagonists in Tartarus itself, such as powerful demons or vengeful spirits that oppose Percy's every move.
Obviously, Percy is the central character. But often, Annabeth can also play an important role, even if she's not physically in Tartarus with Percy in some stories. She might be trying to find a way to rescue him from the outside. Another common character is Nico, who has some knowledge of the Underworld and Tartarus and could potentially be a key figure in helping Percy either survive or escape.
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.
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 will be one of the main characters. Annabeth might also be there, as she often gets involved in Percy's adventures. Grover could be another, as he is Percy's friend and might be there to help Percy deal with the situation of being mistaken for a god. Maybe even some of the gods from the Percy Jackson universe could show up, either to clarify the mistake or to take advantage of it.
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, a plotline could be Percy having to adapt to the extreme and harsh environment of Tartarus. The place is full of darkness and danger. He might have to learn to harness the strange and dark energy that exists there in order to defend himself. There could also be a plot where Percy is forced to make difficult choices. For instance, he might be presented with an option that could save him but at a great cost to others. This would test his moral compass and show how much he has grown as a character in this extreme situation.
One popular story might be 'Percy's Descent' where he faces various challenges in Tartarus. Another could be 'Percy in the Abyss of Tartarus' which focuses on his survival and growth during his time there. There's also 'Tartarus Trials of Percy' that delves into his encounters with the dark creatures of Tartarus.
Perhaps one of the Titans who were banished to Tartarus. They might see Percy as a threat to their plans of revenge or escape. Kronos, if he still has some form of existence in Tartarus, could be a major antagonist. He would have his own motives and powers, and he could try to manipulate Percy or simply get rid of him.
Nico di Angelo could be involved. Since he has some knowledge of the Underworld and Tartarus, he could play a crucial role. He might be the one to guide Annabeth or other rescuers to the right places in Tartarus to find Percy. Also, some of the Titans or primordial deities who have a connection to Tartarus could be important characters, either as obstacles or potential allies for Percy.
Percy Jackson himself would be the main character, obviously. Since he is the God of Matter in this fanfiction. His friends like Annabeth Chase would also likely be important characters. She could be there to support Percy and use her own intelligence to help him understand and control his new powers.