Well, the original Percy has great control over water. But as the son of Ouranos and Gaea, he could have a more fundamental control over the building blocks of the world. He might be able to manipulate the very essence of matter that makes up the earth and the sky. For example, he could potentially turn air into water or vice versa. His powers would be less about the specific domains like water and more about the broader forces that shape the universe. Also, he could have some kind of primordial energy that he can draw on, which is much more powerful and raw than the normal demigod powers.
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 relationship with Annabeth would be very strained at first. Annabeth is used to Percy being a son of Poseidon, and this new revelation would shock her. She might be suspicious of Percy's intentions. But as she sees Percy struggle to be good despite his dark parentage, she would gradually come around. His friendships with other demigods like Grover would also be affected. Grover might be hesitant to be around Percy, fearing that Percy could turn bad. However, as Percy proves himself, their friendship could be rebuilt on a new level of understanding.
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.
One possible plot could be Percy's discovery of his true parentage. He might struggle with the implications of being the son of two powerful primordial deities. For example, he could face a conflict between the forces associated with Ouranos and Gaea. This could lead to him having to make difficult choices about which side to support, if any. And he may also have to deal with the reactions of his friends and the other demigods who might view him differently now.
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.
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.
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.
His powers would be a blend of two very different deities. While still having control over water like the original Percy, he might be able to use his Aphrodite - related powers in combat. For example, he could use his charm to disorient opponents or make them more vulnerable. Also, his connection to the sea might be different. Instead of just controlling the water, he could perhaps make the sea seem more alluring or beautiful, which could be a new form of defense or attack, luring enemies into a false sense of security.
Canon Percy has powers related to water as Poseidon's son. If he were Artemis' son in fanfiction, his powers would likely be more lunar - based. He might be able to control moonlight, for example. He could use it to blind enemies or create illusions. Also, instead of being able to breathe underwater, he could perhaps run at super - fast speeds like the hunters do.
Well, in the original Percy Jackson stories, Percy has powers mainly related to water as the son of Poseidon. But in this fanfiction with Hestia as his mother too, he might have an added connection to fire or the concept of home. So, he could potentially have the ability to control the temperature of water, like making it boil or freeze instantly, which combines his water powers with a bit of the hearth - related powers. He might also be able to create a sort of protective shield around himself and his friends that has the properties of both the ocean's strength and the warmth and safety of the hearth.
One possible plot could be Percy's internal struggle. Since Gaea is often seen as a villain in the Percy Jackson series, Percy would have to come to terms with his dark heritage. He might be shunned by his friends at first. But then, as he discovers that he has the power to control earth and sky elements from his parents, he could use it for good. For example, he could prevent natural disasters that Gaea might have caused in her malevolent state. And he would have to prove to everyone that he is not like his mother, but a hero in his own right.