His powers might be enhanced by Stark technology. For example, his ability to control water could be used in more precise ways with the help of Stark - made gadgets.
When Percy is reborn as a Stark, his powers would undergo a significant transformation. His power of hydrokinesis could be integrated with Stark technology. He could develop a device that allows him to manipulate water on a molecular level, creating new substances or powering advanced machinery. His enhanced physical abilities as a demigod could be augmented by Stark's medical and enhancement technologies. His ability to communicate with sea creatures might be translated into a form of communication with artificial intelligence in Stark's creations. All in all, his powers would be a blend of his demigod heritage and the technological marvels of the Stark family.
His powers could become more nature - oriented. For example, he might be able to control animals better, like Artemis can.
His powers might become more related to fate - manipulation. He could, for instance, foresee certain events related to the destinies of people or creatures. This would give him an edge in battles as he could anticipate the moves of his enemies based on their fated paths.
His powers could become more focused. Kratos might teach him to use his water powers in a more precise way, like creating sharp water blades instead of just large waves.
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.
His powers would likely be adjusted to fit the magical nature of the DxD world. For example, his chakra might be seen as a form of unique magic. His jutsus could be enhanced or modified by the different energies present in DxD.
His powers would likely become more god - like. He might gain the ability to control lightning, like Zeus. Also, his strength and speed could be enhanced to a much greater degree. His control over water, which was his main power before, could also be amplified and perhaps combined with his new lightning powers in some unique ways.
If Percy is a descendant of Kaguya, his powers might change in a way that combines his demigod abilities with some unique Japanese - inspired powers. For example, he could gain the power of illusions, like Kaguya was said to have in some stories. This would be a new and unexpected addition to his combat and survival skills. He could use these illusions to deceive enemies or find hidden paths. Also, his speed and agility might increase, as Kaguya was often depicted as a very graceful and swift figure.
If new elemental powers were introduced, it would change the power dynamics. For example, if a character had the power of shadow as an element, they could use it to surprise enemies or hide important items. This would add new strategies to battles and quests. It could also change relationships. Maybe a character with a new power would be feared or respected more, leading to different alliances.
Percy's powers would be a great addition to the Avengers in a fanfiction. His control over water could create a lot of strategic opportunities. He could flood an area to slow down enemies or create ice platforms for the Avengers to stand on during battles. Compared to Captain America's leadership and combat skills, Percy could offer a different kind of support. And when it comes to Thor, while Thor controls lightning, Percy could use water to conduct that lightning in different ways for more powerful attacks.
His powers might develop in a more self - taught way. Without the guidance of Camp Half - Blood, he'd have to figure out his water - based powers on his own. Maybe he discovers he can control water from puddles in the street to defend himself from attackers.