He might use his powers in creative ways to lessen the impact of the torture. For instance, if the torture involves some form of mental attack, he could try to use his connection to water to calm his mind. Also, his demigod abilities, like his superhuman strength and agility, could help him physically resist some of the more brutal forms of torture to a certain extent. And he may also draw strength from the memories of his past victories and the people he has saved.
Percy might endure it through his own stubborn will. He's a demigod used to facing tough situations. In this fanfiction, he could be using his past experiences of fighting monsters and surviving hardships. He might tell himself that he's been through worse and this is just another trial he has to pass. So he grits his teeth and bears it as best he can, even when the torture in Tartarus is beyond what he's ever faced before.
Well, Percy might endure it through his natural demigod abilities. His connection to the water could potentially be a source of comfort or even a way to resist Kronos' power to some extent. Maybe he can draw strength from the water element around him, even in the midst of torture. Also, his combat skills might help him brace himself mentally, as he's used to facing tough situations in battles.
In some fanfictions, Percy's torture in Tartarus could be part of a grander scheme. For example, an enemy on the surface world has made a deal with the forces of Tartarus to weaken Percy. As he endures the torture, he gradually uncovers the conspiracy and tries to find a way to not only escape but also stop those who sent him there. His friends, unaware of his situation at first, start to suspect something is wrong and embark on a quest to find out what happened to him and rescue him.
He uses his wits. Percy has always been clever, and in Tartarus, he'd use that to his advantage. He'd find ways to outsmart the monsters, like using the environment against them.
Perhaps he could make an alliance with some of the less hostile creatures in Tartarus. There might be beings who are also tired of the chaos and want to help Percy in exchange for something, like a promise to free them from Tartarus if he ever gets the chance. Percy is known for his charisma and ability to make friends, even in the most unlikely situations.
He might use his sword skills and his ability to control water. For example, he could create shields out of water to protect himself from attacks. He would also try to find any weaknesses in his enemies. If there are any water sources in Tartarus, he could use them to his advantage, like making geysers to distract or attack his foes.
He might rely on his skills and the powers he already has. His control over water could help him find sources of water in Tartarus for survival. Also, his combat skills would be crucial in fending off the various monsters there.
He could rely on his natural demigod abilities. His control over water, for instance, might help him find sources of water in Tartarus that are safe to drink or use for protection. Also, his combat skills, which he has honed over many battles, would be crucial in fending off the various monsters in Tartarus.
Grover could also be an ally. His connection to nature might give Percy some unique advantages in Tartarus. Additionally, some of the less hostile creatures in Tartarus, like the friendly Cyclopes, could side with Percy. They might see him as a more just ruler compared to the chaos that usually reigns in Tartarus. Also, Chiron, with his vast knowledge and experience, could offer guidance from afar, which could be considered a form of alliance.
In some fanfictions, Percy Jackson might be depicted as dying in Tartarus. However, this is a departure from the original series. Fanfiction writers often take creative liberties, and some may choose to create such a tragic scenario for shock value or to explore different themes like sacrifice and the finality of death in a harsh, mythological setting.