His powers could be enhanced in some aspects. In the past, the connection between mortals and the gods was stronger. Since Percy is a demigod, he might have a closer bond with Poseidon in an earlier time, which could boost his water manipulation skills. On the other hand, the different magical environment of the past could also bring new limitations. For instance, there could be ancient spells or curses that interfere with his ability to call upon water when he needs it.
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.
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.
In such a fanfiction, Percy might use his knowledge of the future to change some key events in the past. For example, he could prevent some of the earlier disasters or conflicts in the Percy Jackson universe. Maybe he'd try to stop the first encounter with a certain monster in a different way to avoid the chaos it caused.
He could meet his younger self. This would be a really interesting encounter as he could either try to guide his younger self or be shocked at how different he was back then. Another possibility is meeting some of the ancient heroes that he only heard about before. For instance, he might come across Hercules and learn from him.
One interesting plot idea could be Percy going back in time to the era of the Greek heroes. He could meet Hercules and learn from him. Maybe he would have to face the same challenges Hercules did, but with his own modern - day skills and knowledge. Another idea is that he goes back to the time when the gods first emerged and gets involved in the power struggles among them. This could change the entire course of mythology as we know it.
The balance in nature would be disrupted. Artemis is the goddess of the hunt, the moon, and nature. Her death could cause strange phenomena in the natural world, like animals going wild or the moon's cycle becoming erratic. This would not only affect the demigods but also mortals who depend on the stability of nature.
It could be an ancient and powerful Titan who was thought to be defeated long ago. Since Percy is in the past, this Titan could be in his prime and see Percy as a threat to his plans of ruling over the world again. For example, Kronos might be even more powerful in this past era and Percy has to find a way to stop him without the help of his modern - day friends.
Bellatrix's personality could be softened in some ways. Going back in time, she might see things differently. For example, if she goes back to a time when the wizarding world was more peaceful, she could start to question her loyalty to Voldemort. However, she could also become more desperate. If she realizes that she has a chance to change things for the worse in the wizarding world, she might be more eager to carry out her dark plans, and her already - extreme personality could become even more so.
Well, in Percy Jackson fanfiction regarding water powers, it often involves the characters pushing the limits of what's known in the original series. Some fanfictions might show a character using water powers to heal others, as water is often associated with life. There could also be a story where a character with water powers has to face an enemy who has a power that nullifies water, forcing them to find new ways to fight and use their abilities creatively.
In fanfiction, Percy Jackson's lightning powers often get enhanced or modified in interesting ways. Some authors might have him control lightning in more precise forms, like creating lightning cages to trap enemies. It adds a new level of coolness to his already amazing abilities.
There could be a fanfiction where a character with ice powers is actually an enemy in the Percy Jackson world. They are trying to freeze over all the water sources, which would be a huge threat to the demigods. Percy and his friends have to figure out how to stop this ice - powered foe. They might discover that the only way is to find a way to combine fire and water powers in a unique way, like using the heat from Hephaestus - forged weapons along with Percy's water control to melt the ice and defeat the enemy.