Perhaps Percy discovers that his Titan heritage was a carefully planned experiment by an ancient force. This would add a whole new layer of mystery and could change his perception of his family and his purpose. He might then set out on a quest to find out more about this ancient force and its motives. Another plot twist could be that his Titan powers start to corrupt him, but his friends find a way to reverse the process and bring him back to his true self.
A possible plot twist could be that Percy's Titan - born nature makes him immune to certain types of magic that are usually harmful to demigods. This would give him an unexpected advantage in battles.
Well, one possibility could be that Percy has to deal with the new powers and responsibilities that come with being a Titan. Maybe he struggles to fit in with the other Titans who have different values from him. He could also use his new Titan powers to fight against some greater evil that threatens both the Titan and demigod worlds.
One possible plot twist could be that Naruto is born with a special kekkei genkai from Uzushiogakure that was previously unknown. This could make him an even more powerful ninja from the start and change the way the story unfolds. Maybe it's a water - based ability that gives him an edge in combat and makes him stand out not just as a jinchuriki.
One plot twist could be that Ally discovers she has a long - lost relative who is also in the music business and is trying to sabotage her career because of jealousy. Another could be that Jackson fakes his death to get away from the pressures of fame and start a new life, but Ally finds out and has to decide whether to forgive him or not.
A great plot twist could be that Percy's strength is a curse in disguise. He thinks it's amazing at first, but then he realizes it attracts really dangerous enemies. For example, an ancient primordial being that wants to steal his power.
One unique plot twist could be that Percy has hidden powers from his Titan heritage that no one, not even the gods, expected. For example, he might be able to control time in a small way, which is a power not associated with his normal demigod abilities.
One possible plot twist could be that Hermione, being a vampire, has to hide her true nature from her friends at Hogwarts. This would create a lot of internal conflict for her as she values her friendships but also has to deal with her new vampiric instincts. Another twist might be that she discovers she has special vampire powers that no one else has, which could lead to her being both feared and sought after in the wizarding world.
Well, perhaps a plot twist could be that Percy's friends think he's been kidnapped by someone else entirely. So they're looking in all the wrong places while Khione has him hidden away. Or, it could be that Khione kidnaps Percy but then realizes she's made a huge mistake because Percy has some sort of connection to a force that can destroy her. So she has to figure out a way to either let him go or use him to her advantage in a different way. Also, what if Percy is able to communicate with the elements in Khione's domain and he uses that to his advantage to escape or gain the upper hand?
Maybe Percy loses his powers temporarily during the battle with Typhon. This would completely change the dynamic of the fight and force him to rely on his wits and the help of his friends in a whole new way. He might have to find a magical item or perform a heroic deed without his powers to turn the tables on Typhon.
Well, it could be that when Percy looks at Medusa, their minds get swapped. Percy then has to figure out how to use Medusa's powers and body to his advantage while also trying not to get killed by the heroes who are coming after 'Medusa' (who is really Percy in her body). And Medusa, in Percy's body, has to deal with his life, like his relationships with Annabeth and his friends at Camp Half - Blood, which could lead to some really interesting and comical situations.
Well, a great plot twist could be that Percy is turned into a vampire but he was actually part of an ancient prophecy in the vampire world. As he struggles to adapt to his new life, he finds out that there are vampire hunters who are after him not just because he's a vampire, but because they believe he will bring about a great change in the vampire - human balance. Also, his transformation could be different from other vampires. Instead of craving blood right away, he has a strange attraction to something else, like the essence of magic, which is very un - vampire - like and causes confusion among the vampire clans.