Well, if Percy was the son of Loki and Poseidon in fanfiction, his powers would be a really wild mix. He might have Poseidon's control over water, but with a Loki - like trickster twist. For example, he could create illusions in the water, making it seem like there are sea monsters when there are none to deceive his enemies. He could also use Loki's shape - shifting ability while in the water, perhaps turning into a mermaid - like form with a mischievous glint in his eyes. His power over water could also be used in more devious ways, like creating whirlpools that suck in his foes and then spit them out in a different location, all while laughing like Loki would.
If Percy were the son of Loki and Poseidon in fanfiction, his powers would be a blend of the two. He would likely have enhanced water - based powers from Poseidon. For instance, he could control not just regular water but also things like ice and steam more effectively. From Loki, he could get the power of misdirection. So when he uses his water powers, it would be hard for opponents to tell where the attack is really coming from. He could also use Loki's ability to charm - speak to some extent, convincing sea creatures to do his bidding in a more manipulative way than just a normal connection from being Poseidon's son.
His powers would be extremely different. Since Poseidon gives the ability to control water, and Loki is known for his cunning and trickery, Percy could have the power to manipulate water in a deceptive manner. He might be able to make water seem solid to walk on, but then suddenly make it turn back to liquid when his enemies step on it. Also, he could inherit Loki's power to create duplicates of himself made of water, confusing his opponents in battle. And with Poseidon's connection to sea creatures, he could communicate with them in a more Loki - style, using them to play pranks on people or to gather information stealthily.
Well, instead of summoning water or having a connection with the sea, he might have the power to shift shapes, a common ability associated with Loki. He could turn into different animals or even other people to gain an advantage in a fight or to infiltrate an enemy's stronghold. Also, his power over fire could be enhanced, as Loki has some association with fire in Norse mythology. He could use this to create distractions or attack opponents from a distance.
His water - based powers might be more intense. Since he's directly related to Poseidon, he could have greater control over large bodies of water, like being able to create huge tidal waves with just a thought, instead of just small ones. He might also be able to communicate with sea creatures on a deeper level, understanding their complex languages and using them to his advantage in ways he couldn't before.
In a fanfiction where Percy is the son of Hades and Poseidon, his powers would be truly extraordinary. He could have the ability to create portals in water that lead to the Underworld. This would give him an advantage in both battle and travel. His hydrokinesis could be tainted with the essence of death, so when he attacks with water, it could cause a draining effect on his opponents, sapping their life force. Additionally, he might be able to sense the presence of the dead in any water source, which could be used for both reconnaissance and protection.
If Percy were the son of Poseidon and Hera, his powers would be quite unique. His water powers could be enhanced in a different way. Maybe instead of just controlling water, he could transform water into different substances related to Hera's domain, like turning water into a fertile soil - like substance for plants to grow. His leadership skills would be off the charts. He could use his Poseidon - given strength and Hera - influenced charisma to lead not just demigods, but also other mythical creatures. He might also have the power to protect a place or a group of people in a more profound way, like creating a shield made of both water and a golden energy that represents Hera's protection.
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.
Percy's powers would be more complex. He could have the ability to communicate with sea deities in a different way. Maybe he could use Hera's diplomatic skills to make deals with them or resolve disputes. His control over water could also be extended to other substances that have a connection to water, like steam or ice, in a more efficient way than before. And his powers of persuasion, which could be influenced by Hera, might be used to calm angry sea storms or make sea monsters cooperate with him, which is an interesting combination of his Poseidon - given powers and Hera - influenced skills.
His powers would likely be much darker. He might have the ability to manipulate shadows like Nyx, using them to hide or even attack. And from Tartarus, he could have the power to cause earthquakes or open up chasms in the earth. He could also have a natural resistance to the harmful effects of the Underworld, such as the poisonous gases and the draining of energy that normal demigods experience.
His powers would likely be a blend of Greek and Norse elements. For example, he might still be able to control water like in his Greek demigod abilities, but also have some connection to ice or snow from the Norse side. Maybe he could freeze water in a way that's more related to Norse frost magic.
Percy could have the power to manipulate the coldness that is often associated with the Underworld. He could freeze his opponents or create ice - like structures out of the cold energy. This would be different from his water - based powers in the normal story. Also, he may have a stronger connection to the gems and precious metals that are found in the Underworld, being able to sense them and even use them in some way for his benefit.
Percy's personality would be a complex mix. From Poseidon, he would inherit a sense of loyalty and a connection to nature, specifically the sea. However, Loki's influence would make him more devious. He could be the kind of person who would seem trustworthy on the surface, but then pull a fast one on you when you least expect it. He'd have a love for adventure like the original Percy, but his methods of getting into and out of trouble would be more elaborate and sneaky. He'd also be very good at getting out of sticky situations using his wits, which he'd get from both his 'parents' in this fanfiction scenario.