Annabeth would be a likely character to appear. Since she and Percy are so close, she might try to find a way to rescue him from Tartarus. Another character could be Nico. He has experience with the Underworld and might be able to offer some help or advice. Grover could also show up, using his nature - related powers to try and sense Percy in Tartarus.
Some minor characters from the original series could also play a role. For example, the Stoll brothers might try to steal some powerful item from Tartarus while Percy is there and get caught up in his adventure. Or Clarisse, with her tough - as - nails attitude, could come to Tartarus to prove herself and end up helping Percy in some way.
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.
If Percy Jackson is sent to Tartarus in fanfiction, it could be a harrowing experience. First off, the environment itself is a nightmare. The terrain is dangerous and full of pits and lava. Percy would have to rely on his wits as much as his strength. Since Tartarus is the prison for the most powerful Titans and monsters, he'd be up against foes far more powerful than he's used to. He might even discover some long - lost secrets about his powers or his family's past while trying to find a way out.
One interesting plot could be Percy's struggle to survive in Tartarus alone. He might have to face the various monsters there without his usual allies. Another plot could involve him finding a way to escape Tartarus using his wits and the powers he has. Maybe he discovers some secrets about Tartarus that no one else knows.
The plot could revolve around Percy's journey of self - discovery in Tartarus. Sent there unjustly by the gods, he could start to question his past actions and his relationship with the divine. As he battles the horrors of Tartarus, he may develop new powers or skills. He could also be on a mission to expose the true nature of the gods' actions, which led to his banishment to Tartarus. Along the way, he would face challenges that test his physical and mental strength to the limit.
A third plotline could be about Percy's mental and emotional state during his banishment. He could be dealing with feelings of betrayal, as he was banished. He might question his identity and purpose, and throughout the fanfiction, he gradually overcomes these doubts and insecurities, emerging stronger in character even if he's still trapped in Tartarus.
One possible reason could be jealousy among his so - called friends. Maybe someone was envious of Percy's powers or popularity and decided to frame him, leading to his betrayal and subsequent sending to Tartarus. Another reason might be a misunderstanding. For example, if there was some false evidence planted against Percy, his comrades could have been misled into believing he had done something unforgivable and sent him to that horrible place.
One possible plotline could be Percy's struggle for survival in Tartarus. He might face various terrifying monsters and have to use his wits and powers to stay alive. Another could be his journey of self - discovery in that dark place, realizing new aspects of his abilities or his past. Maybe he also tries to find a way to escape Tartarus while also dealing with the psychological toll of being in such a desolate and dangerous realm.
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. 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.
It's possible that some of Percy's old enemies, like Kronos' minions who somehow survived, might resurface in this fanfiction. They could be trying to stop Percy from achieving whatever goals Chaos has for him. Also, some of the gods might get involved. They could be curious about Percy's new situation, or they might be worried that Percy's new power under Chaos could be a threat to them. And then there could be some mysterious entities from the Chaos - related realms that we haven't heard of before in the original Percy Jackson stories.