In some fanfics, Percy's powers could be used in a more stealthy way. For instance, he could use water to create mirages or illusions to deceive his enemies. This would require a great deal of control over his water - based abilities and show his growth as a character. It also allows for more complex and exciting plotlines in the fanfic world.
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.
His ability to communicate with sea creatures might seem strange for football, but what if there are some sort of water - based spirits in the stadium's plumbing? He could get some 'inside information' about the field conditions or even use them to spook the opposing team. Also, his enhanced strength as a demigod would surely make him a force to be reckoned with when it comes to tackling or blocking.
In fanfiction, Percy Jackson's powerful water powers can be depicted in various ways. Some might show him creating massive tidal waves to defend against powerful foes. For example, he could use his powers to flood an entire battlefield, leaving his enemies struggling to stay afloat while he and his allies remain in control. This showcases the sheer scale of his water - based abilities.
His water - based powers might become corrupted. Instead of just controlling clean, life - giving water, he could now also manipulate dark, poisonous waters from the depths of Tartarus. This would make his powers more dangerous but also more unpredictable.
His powers could also be more regulated. The Roman military has a strict code of conduct, so Percy may not be able to use his powers as freely as he did as a Greek demigod. He might have to get permission from his superiors before using his powers in combat or for other tasks. This could lead to some interesting situations where he has to hold back or find alternative ways to solve problems.
His water - controlling power would be a huge advantage. For example, during naval operations, he could manipulate the sea to create safe passages or disrupt enemy ships. Simple as that.
If Percy is thrown back in time, his powers could be enhanced. In the past, magic and the power of the gods were more prevalent. The very air might be charged with more divine energy. His ability to communicate with sea creatures could expand, as there could be species that are now extinct or have evolved in his own time. However, he might also face limitations. For example, if he goes back to a time when the gods were at war, some of his powers related to Poseidon might be restricted depending on his father's situation in that war.
His water - based powers might be affected in different ways. If he goes back to a time when the oceans were less polluted, the purity of the water could make his powers stronger. However, if he goes to a time when the gods were more in control of the elements, they might be able to limit his power. For example, Poseidon might have more say over how Percy can use water powers if they are in the same time period.