Well, perhaps in the fanfic, there's a prophecy that gets misinterpreted. The gods think Percy is going to cause great harm based on this wrong interpretation, so they send him to Tartarus. It could also be that there's some sort of power struggle among the gods. Percy might be caught in the middle of it, and one side decides to get rid of him by banishing him to Tartarus to tip the balance in their favor.
First of all, Percy's resourcefulness would come into play. He would probably try to make allies among the less - hostile creatures in Tartarus. He has a way of befriending those who are often overlooked. Also, he would use his knowledge of Greek mythology. Since he knows about many of the monsters and their weaknesses from his studies, he can use this knowledge to survive. His connection to his friends, even if they are far away, might also give him the strength and motivation to keep going and find a way to escape or at least endure.
He might rely on his powers. Percy is a son of Poseidon, so his control over water could be crucial. He could use water sources in Tartarus, if any, to heal himself, create barriers, or even find a way to escape. For example, he could manipulate the Styx water to his advantage.
In the fanfiction, the environment of Tartarus itself could be considered an antagonist. The extreme heat, the toxic gases, and the ever - present danger of falling into bottomless pits. And on top of that, there could be some sort of demon - like creatures that are specifically created or summoned to hunt down Percy and Zoe and prevent them from achieving their goals.
Well, one possible plot could be that Percy and Zoe have to face various ancient and terrifying monsters in Tartarus. They might encounter challenges that test their friendship and their individual strengths. For example, they could come across the Titans that were once banished there, and have to find a way to avoid or defeat them while also trying to find a way back to the upper world.
Well, one aspect to consider in this fanfiction could be the character development. Percy Jackson is already a well - established character, but as the heir of Tartarus, he might face new challenges that force him to grow in different ways. Maybe he has to deal with darker powers within himself. Another point could be the world - building. Tartarus is a very dark and dangerous place in the Percy Jackson universe, so how the author expands on that and shows its influence on Percy and the story is important. Also, the relationships with other characters would be interesting. Will his friends still trust him when they find out he has this new 'heir' status? How will his enemies react?
They might survive by relying on their combat skills. Percy, with his sword - fighting abilities and Zoe's archery skills, can fend off the various monsters in Tartarus. Also, they could use the environment to their advantage. For example, hiding in the dark corners or using the natural formations as shelters.
Perhaps a prophecy misinterpretation. If a prophecy was misread and it seemed like Percy was the cause of great evil to come, the gods might take drastic action. For instance, if the prophecy spoke of a 'child of the sea' causing destruction, and they wrongly assumed it was Percy without fully understanding the context.
Well, in many fanfictions, Percy might be on a mission to assassinate some powerful being in Tartarus. Maybe he has to face all kinds of hellish creatures and overcome insane challenges. It could involve him using his water powers in unique ways, like creating weapons out of water to fight the demons of Tartarus.
This is a really interesting concept. In the original Percy Jackson series, Percy is the son of Poseidon. But in this fanfiction idea, if he were the son of Gaea and Tartarus, it would completely change his character and the story. His powers would likely be much darker and more primal. He might have an in - depth connection to the earth and the abyss, which could lead to some really unique storylines.