A plot twist could be that Percy has a connection to the primordial forces that even the Titans and the Olympians are afraid of. His link to Nyx and Tartarus means he can access parts of the universe that are normally off - limits. For instance, he might be able to open portals to the darkest corners of Tartarus, which could either be a great advantage or a huge danger. Also, he could have the power to call upon the creatures of the night created by Nyx, and these creatures could be either his allies or a threat to the existing order of the demigod world, depending on how Percy chooses to use his powers.
Perhaps Percy discovers a prophecy related to his birth. It could state that he is the key to either saving or destroying the world. This would create a lot of internal conflict for him. On one hand, he has his friends and the people he cares about in the mortal world. On the other hand, his powers and his role according to the prophecy could force him to make some very difficult choices.
Well, a plot twist could be that Percy's connection to Tartarus gives him the ability to control the very essence of the underworld. This means he can manipulate the shadows and the dark magic there. But because of his Lupa heritage, he also has a strong sense of loyalty and pack mentality. So, he forms an unlikely alliance with some of the more 'civilized' monsters in the underworld who also follow a code of honor. His friends from Camp Half - Blood are initially very skeptical and even a bit scared of him, but as they learn more about his new powers and how he's trying to use them for good, they start to come around.
One plot idea could be Percy struggling with his new identity. Since Tartarus and Nyx are such powerful and dark entities, Percy might have to battle against the dark urges within him. He could be shunned by his friends at first, but then prove that he's not defined by his parentage. For example, he might save Camp Half - Blood from a new, powerful threat using his unique powers that come from his heritage.
A really wild plot twist could be that the blessing is actually a ruse by Tartarus to use Percy as a pawn in a bigger scheme against the gods. Percy, being the hero he is, would have to figure out what Tartarus is up to and find a way to turn the situation around. This would involve him having to face some really tough challenges and make some difficult decisions.
His powers would likely be much darker. He might have the ability to manipulate shadows like Nyx, using them to hide or even attack. And from Tartarus, he could have the power to cause earthquakes or open up chasms in the earth. He could also have a natural resistance to the harmful effects of the Underworld, such as the poisonous gases and the draining of energy that normal demigods experience.
One possible plot twist could be that they discover a hidden power within Tartarus that allows them to communicate with the gods in a way they couldn't before. This new connection might lead to a deal where they can earn their freedom by completing a near - impossible task for the gods. Another twist could be that they find an ancient prophecy written on the walls of Tartarus that foretells their role in saving not just themselves, but the entire world from a greater threat that the gods are unaware of. Or perhaps they encounter a long - lost civilization of powerful beings in Tartarus who offer to help them escape in exchange for a future favor that will put Percy and Zoe in a difficult moral dilemma.
One possible plot twist could be that Percy, as the son of Hades and Hera, discovers a hidden power within him that can control both the underworld and the aspects of Hera's domain like marriage and family. This power could put him in the middle of a great conflict between the gods who are jealous of his unique abilities.
One possible plot twist could be that Percy has to hide his true parentage from his friends at Camp Half - Blood. Since Lycaon was a werewolf - like figure and Lupa is associated with wolves in Roman mythology, Percy might have some wolf - like abilities that he doesn't understand at first. For example, he could have enhanced senses like better smell and hearing, which could make him seem different from other demigods. Another plot twist could be that there are other characters who are secretly aware of his true parentage and are either trying to protect him or use him for their own purposes.
Perhaps a plot twist could involve Kronos' essence trying to take over Percy's body. Percy would have to fight against this internal takeover, and in the process, he discovers a way to use Kronos' power for good. This would completely change the dynamics of the Percy Jackson universe as we know it, with Percy becoming a sort of anti - hero figure who uses the power of the enemy to protect his friends and the world.
Perhaps a really interesting plot twist could be that Percy's adoption by Erebus reveals a long - lost prophecy. This prophecy states that Percy, with his combined heritage of being Poseidon's son and Erebus' adopted son, is the key to either the destruction or the salvation of the entire Greek mythological world. This would put Percy in a very difficult position as he tries to figure out how to fulfill the prophecy in the best way possible, all while dealing with the reactions of other gods, demigods, and mythical creatures.