His powers would be much more extreme. Instead of just controlling water like he does as a son of Poseidon, he could control light and air elements. His connection to Aether could give him the ability to manipulate the very fabric of the upper atmosphere. And from Hemera, he might have the power to bring instant daylight or even manipulate time related to the day - night cycle.
Well, it could be about Percy's unique powers inherited from Aether and Hemera. Maybe he can control light and darkness in new ways. He could use the powers of Aether, like the upper air or the heavens, to fly or teleport. And the powers from Hemera, the day, might give him enhanced strength during daylight hours.
His powers would likely be much more elemental. Since Ouranos is associated with the sky, he might have powers over the air, such as creating powerful winds or even controlling the weather on a greater scale than before. And from Gaea, he could have enhanced earth - based powers like causing massive earthquakes or having a deeper connection to the land, perhaps being able to communicate with all forms of plant and animal life that are rooted in the earth.
His powers would likely be a blend of his original demigod abilities and those of Odin. He may still retain some connection to water, but it could be transformed. Maybe he can turn water into ice like the Norse frost giants. Also, he could have Odin's gift of knowledge, which means he could understand ancient languages or know things about the past and future without being taught. This would give him an edge in battles and quests compared to the original Percy.
Well, a great idea for 'Percy Jackson Son of Aether' fanfiction would be to explore his relationship with the other gods. Since Aether is an important and somewhat mysterious entity, the gods might be either jealous or intrigued by Percy. He could face challenges from the gods who don't want a new 'son of' disrupting the status quo. Also, his adventures in the underworld could be different. Maybe he can use his Aether - related powers to see things that are usually hidden there, like secret passages or lost souls that hold important secrets.
The Titans could be great antagonists. They might see Percy as a threat to their plans of regaining power. Since he has the power of Aether, they could fear that he'll be able to stop them in ways other demigods can't. Another option could be some dark demigods who are jealous of Percy's connection to Aether and want to steal his powers for themselves.
In this fanfiction, Percy would likely have powers related to both Apollo and Athena. Canon Percy has water - based powers from Poseidon. But here, he might have the ability to heal like Apollo, which would be a huge difference. He could also have enhanced intelligence and strategic thinking from Athena. So instead of just relying on his strength and water powers in battles, he could use his wits and healing abilities as well.
Percy as the son of Vulcan would likely be more analytical. In the original, he was quite impulsive. But now, with Vulcan's influence, he might think more before acting. For example, instead of immediately jumping into a fight, he would assess the situation and figure out the best way to use his new powers, like creating a strategic weapon on the spot. He could also be more introverted as he delves deeper into his new abilities and the mysteries of his new heritage. He may spend more time alone in Vulcan's forges, tinkering and thinking, rather than being out with his friends all the time.
Percy could use his water - controlling powers in combination with Wolverine's adamantium claws. For example, he could cover his claws with water and freeze it, creating ice - blades that are even more deadly.
His powers would likely be a blend of Kronos' and Rhea's. Kronos was associated with time, so Percy might have some control over time. He could slow it down or speed it up in a small area. Rhea was a mother goddess, so Percy might have a strong connection to nature and the ability to heal. This is different from his original powers as Poseidon's son where he mainly had control over water and could communicate with sea creatures.
The main difference is the setting. While the original series has Percy in the normal world of demigods, fanfiction about purgatory takes him to a completely different realm. Here, the rules and challenges are likely to be very different.