One potential plot twist could be that Percy is not actually the son of Helios as he initially thought. Maybe it was a trick by a villain to mislead him and gain access to the power associated with Helios.
One potential plot twist could be that the gods try to keep his true parentage a secret, but Percy discovers it through a series of strange dreams or visions. Another could be that he has a power that is completely unexpected, like the ability to combine the powers of the moon (from Artemis) and the sea (from Poseidon) in a way that no one has ever seen before. For example, he could create tidal waves that are influenced by the phases of the moon.
Well, perhaps a plot where Percy is tasked with protecting a group of mortals from a new threat that emerged because of a disruption in Helios' power. He has to use his powers, which might include some solar - based abilities like controlling light or heat, to fend off the danger. Along the way, he could make new allies and enemies, and learn more about his father's past and his own potential.
It could be a story where Percy, as the son of Helios, discovers his unique powers related to the sun. Maybe he can control sunlight to create illusions or use it as a powerful weapon against his enemies.
Obviously Naruto himself. Then there could be new characters related to Helios' realm, like solar - powered guardians who come to protect Naruto or teach him about his heritage. Also, the existing Naruto characters would still be there. Sasuke might be intrigued or even jealous of Naruto's new powers. Sakura could be worried about how Naruto's new identity might change him.
One potential twist could be that Percy is actually undercover for the good guys all along while pretending to join Gaea.
A really cool plot twist could be Percy finding out he has a long - lost sibling who is on the side of the Titans. This would create a huge internal conflict for Percy as he has to decide between his loyalty to his new - found family and his duty to the Olympians. It would also add a lot of drama and tension to the story as he tries to sway his sibling to the right side.
One common plot twist could be Percy discovering that his connection to Artemis brings some unforeseen powers. For example, he might gain the ability to communicate with certain animals that are sacred to Artemis. Another could be that there's a prophecy about him that was hidden until a crucial moment, changing the course of his journey. Or perhaps he finds out that his parentage is more complex than he thought, with some dark secret related to Artemis that others have been hiding.
One common theme is identity. Percy has to figure out who he is now that he's the son of Helios, different from his previous understanding of himself as Poseidon's son.
One plot twist could be that Harry's real father was not James Potter but an unknown figure from Hawkgirl's world. This would completely change the dynamics of his family story. Another could be that Voldemort discovers Harry's Hawkgirl heritage and tries to use it against him by creating a spell that combines dark magic with the technology or powers associated with Hawkgirl's world.
Well, it could be about Naruto having special powers inherited from Helios. Maybe he can control a new type of sunlight - based jutsu. For example, he could create blinding flashes to stun his enemies or use the heat of the sun to enhance his physical attacks.