Perhaps he would gain the power of immortality in a more profound way. Normal gods can be killed under certain circumstances, but as a new kind of god, Percy could be truly indestructible. He would no longer have to worry about threats from Titans or other powerful entities, and could focus on ruling over his domain, which might be a combination of the sea and something new, like the protection of demigods everywhere.
One of the new powers could be the ability to control all forms of water in a much greater scale. Not just the sea, but also clouds, rivers, and even the water in living beings. This would make him extremely powerful as water is everywhere. He could use this power to create massive tidal waves or to heal by manipulating the water within a body.
Well, his powers might include not only water - based ones. Since he's a god, he could have some sort of divine influence over weather related to the sea, like creating massive storms or calming them at will. He might also gain the power to transform into different sea - related forms, such as a giant sea monster or a merman - like being. And his healing ability, which was already there because of his connection to water, could become so strong that he could revive the dead if they had a connection to the sea in some way.
If Percy was the son of Gaia and Tartarus in fanfiction, his power set would be a fascinating blend. From Gaia, he could potentially have the power of terraforming, reshaping the earth on a large scale. He might also be able to communicate with all forms of earth - bound life. From Tartarus, he could gain the ability to traverse the darkest depths of the underworld with ease, and perhaps even draw power from the primordial chaos there. This would make him a very different and much more complex character compared to his original form in the official series.
He could have the power to freeze water instantly. Since he has a connection to water already as a son of Poseidon, this would be an extension of that. He might also be able to create ice storms and blizzards at will.
One new ability could be ice - skating at super - speeds. He could glide across water or land, using his ice - skates made of pure ice, and quickly reach his destination or dodge attacks. It would be like a combination of his natural athleticism and his new ice powers.
One significance is that it expands the possibilities of his character arc. He goes from a hero to a god - like figure, which is a huge transformation. It allows for different types of challenges and growth. For example, he may face moral dilemmas about how to use his new - found power.
Perhaps he gets the power of astral projection. He could send his spirit out of his body to explore areas that are otherwise inaccessible or to spy on his enemies. This would be a very useful power especially when dealing with secretive foes or trying to find hidden places in the mythological world.
One possible new power for Percy Jackson in fanfiction might be the ability to communicate with all types of mythical creatures, not just those related to the sea. This would expand his network of allies and give him more knowledge about the mythical world.
Well, in fanfiction, Percy could have the power to control storms on a global scale. Imagine him summoning massive hurricanes to defeat his enemies or using gentle rain to heal the land. It would be a huge upgrade from his existing water - based powers.
In Percy Jackson new elemental powers fanfiction, the power of time could be a new addition. A character might be able to slow down or speed up time in a small area, affecting the elements within it. For instance, if they slow down time around a fire, it would seem to burn more slowly. Also, the power of space could be introduced. This could allow a character to manipulate the space between elements, like pulling water from a far - off source or compressing air to create a powerful blast.
If new elemental powers were introduced, it would change the power dynamics. For example, if a character had the power of shadow as an element, they could use it to surprise enemies or hide important items. This would add new strategies to battles and quests. It could also change relationships. Maybe a character with a new power would be feared or respected more, leading to different alliances.