The plot could twist in a way that Percy, as a kid, is transported to a different time or dimension. Maybe he's sent back to the time when the gods first made contact with demigods. Since he's a kid, he has no knowledge of this history, but he has to quickly adapt and figure out how to get back home. His child form might make it easier for him to interact with the ancient demigods in some ways, but also more difficult in others because they might not take him seriously. This would be a huge plot twist as it changes the entire setting and context of the story.
Well, one plot twist could be that Percy, as a kid, doesn't remember his heroic deeds. This would lead to him being confused when strange things start to happen around him. For example, monsters might still be after him, but he has no idea why. Another twist could be that his demigod powers are affected in strange ways. Maybe his control over water is now more like a child's wild and unpredictable outbursts. Also, his relationships with his friends would change. They'd have to protect him instead of the other way around, and it would be a whole new dynamic for them to deal with.
One possible plot could be that Percy, upon turning into a goddess, has to deal with the new powers and responsibilities. He might struggle to adapt to the more feminine aspects of the goddess form. For example, if he turns into Aphrodite, he could be forced to spread love and beauty in ways he's not used to, like matchmaking among the demigods, which could lead to some really comical and also heart - warming situations as he tries to understand the true meaning of love from a different perspective.
One possible plot twist could be that Percy wearing a dress is part of a disguise to infiltrate a group that only allows females. For example, he might be trying to retrieve a powerful magical item that is guarded by this all - female group. Another plot twist could be that it's a magical curse that forces him to wear a dress until he completes a certain task, like solving a riddle or making amends with a certain deity. And perhaps the dress is enchanted and gives him special powers that he has to learn to use while also dealing with the embarrassment of wearing it.
One possible plot twist could be that Percy discovers a hidden power within himself during the battle. Maybe he realizes he can control not just water, but also the heat from the hot springs in Thermopylae, using it to his advantage against the enemies. This new power could turn the tide of the battle in an unexpected way.
Well, a plot twist could be that her immortality is actually a curse in disguise. Maybe she becomes immortal but is then trapped in a time - loop where she has to relive a particularly bad event over and over again until she figures out how to break it. Or perhaps she's made immortal but then realizes that she can no longer interact with the mortal world in the same way. She can see her friends and family age and die while she remains the same, which causes her a great deal of emotional pain. Also, she could discover that her immortality was granted by a rogue god who has his own evil plans for her, and she has to fight against this god's control.
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.
One possible plot twist could be that Percy has hidden powers related to Kronos. Since Kronos is a powerful Titan, Percy might have some latent abilities that are similar but not as malevolent. For example, he could have a unique control over time on a small scale, like being able to slow down time briefly in a battle to gain an advantage. Another plot twist could be that the gods initially mistake Percy for being as evil as Kronos due to their relation. This would lead to Percy having to prove his loyalty to the gods and his friends all over again. He would face a lot of distrust and have to overcome many challenges to show that he is not like his 'twin' in nature.
A plot twist could be that Percy's blindness is a disguise by the gods. They made him blind to protect him from a prophecy that involves his sight. As he grows up, he discovers this truth. Also, in the world of Percy Jackson, there are many magical creatures. A plot twist could be that a certain creature, like a cyclops, takes pity on him because of his blindness and becomes an unexpected ally. This cyclops could have some unique knowledge about his blindness or a way to overcome it that no one else does.
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.