If Harry is reborn as Percy, his magic would likely be influenced by the water - based powers Percy has. He could use water to conduct his magic, similar to how Percy can control water. His magic could also be affected by the presence of Greek gods. They might either enhance or restrict his magic depending on their relationship with him.
His magic would need to fit into the world of Percy Jackson. So, instead of using a wand all the time, he might learn to channel his magic through his hands like other demigods use their powers. His spells could also be modified to suit the Greek - themed world. For example, instead of saying 'Lumos' to create light, he might say a Greek - inspired incantation that also creates light, but in a way that is more in tune with the new world he's in. This adaptation would not only be a matter of survival but also a way to integrate into the demigod community.
Naruto's ninja skills would have to adapt in several ways. His tracking skills, which he learned as a ninja, could be used to find lost demigods or track down powerful monsters. His ability to sense danger, which was related to his chakra sensing in the Naruto world, could be translated into a new form of danger - sensing in the Percy Jackson world. He could also use his ninja - style parkour skills to traverse the different terrains in the Greek mythology - based world, like climbing the sides of Mount Olympus or running across the rooftops of ancient Greek cities. And his skills in using ninja tools could be combined with the use of demigod weapons, creating a whole new combat style.
In a fanfiction, Percy's adaptation to Hogwarts would be a bumpy but interesting ride. He'd be constantly comparing Hogwarts to Camp Half - Blood in his head. At first, he might struggle with the lack of open combat training like he has at camp. But he'd discover that the dueling club at Hogwarts can be a substitute. He'd have to adapt to the different social hierarchies too. The pure - blood, half - blood, and Muggle - born concepts would be new to him. He'd probably see similarities to the god - parent, demigod, and mortal distinctions in his world. His loyalty to his friends from Camp Half - Blood would remain strong, but he'd gradually develop new loyalties at Hogwarts as well.
Well, he might bring his demigod skills to Hogwarts. He could be really good at Defense Against the Dark Arts, using his combat experience from fighting monsters. And his ability to adapt quickly, which he had in the Percy Jackson world, would help him in the wizarding world too.
He'd have to learn the new rules. Percy is used to the Greek pantheon's way of doing things, but in Asgard, it's a whole different ballgame. He'd probably start by observing how the Norse gods and their followers interact. And he might use his charm, which has served him well in the Greek world, to make friends among the Norse.
Percy would likely first be shocked by the cold in Skyrim. But he'd quickly adapt his powers. He could use his control over water to deal with the snow and ice, maybe even creating steam to warm himself up. His fighting skills with a sword from his demigod training would be useful against the bandits and monsters in Skyrim.
Percy would need to learn how to be stealthy. He's used to fighting out in the open as a demigod, but as a ninja, he'd have to blend into the shadows. He could use his powers over water to create distractions or cover his movements, like making a mist to hide in.
He'd probably have a hard time at first. The weather in Forks is very different from what he's used to. Also, the small - town atmosphere might be a bit suffocating for someone who's used to the more adventurous life of a demigod. But he'd adapt by using his skills. His athleticism from all his training as a demigod would make him stand out in school sports, which could be a way for him to make friends.
Percy would probably have to adapt to the different cultural norms. For instance, the Soviet Union had a very different social and political structure compared to what Percy is used to. He might initially struggle with the more collective mindset. However, his ability to adapt quickly, which he has developed from his various adventures in the Percy Jackson series, would help him. He could start by learning the Soviet language, which would be essential for communication.
His water - based powers could be affected in various ways. If the new world has different types of water or water - like substances, he might need to learn how to control them. For example, if there's a magical liquid, he could potentially manipulate it. His demigod strength and speed might also be enhanced or restricted depending on the new world's physical laws.
His confidence would still be there but might be a bit more subdued as he adjusts to the new world. He's used to being a big shot among demigods, but in Hogwarts, he has to start from scratch.