Well, in his new life as a baby, he might grow up with a different family. Maybe he won't face the same initial hardships. He could be raised in a more stable environment, which would change his whole perspective. His relationships with the gods might also start off on a different foot. Instead of the rushed and often dangerous encounters he had before, he could have a more gradual and perhaps less hostile introduction to the world of the divine.
One big difference could be his training. In his original life, his training was sort of ad - hoc and in the midst of danger. Reborn as a baby, he might receive proper, formal training from an early age. This could make him even more powerful and better - equipped to handle the challenges that come with being a demigod. Also, his friendships might form in a different way. He could befriend different people in his new life, which would impact his adventures later on.
If Percy Jackson is reborn as a baby, his understanding of his powers could be very different. In his first life, he discovered his powers in the heat of battle and through a series of dangerous events. As a baby, he might grow up knowing about his powers from the start, which would change how he uses them. He could also have a different attitude towards the gods. Maybe he'd be more curious and less resentful since he'd have a fresh start without all the past grudges.
It would be really interesting. Since he's reborn as a baby, he and Annabeth wouldn't have the same initial connection. Annabeth might first see him as just a cute baby, not the hero she knew. Their relationship would have to build from scratch. She might be more protective of him at first, like an older sister figure, and as he grows up, their relationship could develop into a romantic one in a much more gradual way compared to their previous life.
If Percy relives his life, he could completely rewrite the prophecy. He may not make the same mistakes that led him to fulfill the prophecy in the original way. Instead, he could find new ways to deal with the threats to the demigod world, like finding alternative solutions to the problems caused by the Titans and the Giants. He could also have a chance to explore more about his mother's side of the family, which was not much delved into in the original story.
If Percy Jackson were to redo his life in fanfiction, it would be a wild ride. He might start by being more upfront with his mother about his strange experiences. He could then take steps to better prepare himself for the world of demigods. Perhaps he'd form alliances with other demigods sooner, and they could all work together to face the threats from the start. This could lead to a completely different power dynamic in the demigod world. He might also have a chance to explore his powers more deeply without the immediate pressure of constant battles and quests.
It would be amazing. You could be a demigod with unique powers. Maybe you'd be at Camp Half - Blood, making friends with Percy and his friends. You could go on quests, face mythical monsters, and discover your own story within the rich world of Percy Jackson.
As a baby, Percy's character development would start from a very innocent and instinct - driven state. Instead of the typical teenage bravado, his early development could focus on his natural abilities emerging in a more uncontrolled way. For example, he might accidentally zap things with his water powers when he's excited or scared.
If reborn into this fanfiction, your life would be full of new challenges. You'd be part of a community of demigods, which means there would be a whole set of rules and hierarchies to follow. You might start off as a nobody but through your actions on quests, you could become a hero. You'd also be constantly in danger from monsters sent by the gods who don't like you or your parent god.
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.
He'd probably be more brooding. Growing up with Hades, he'd be exposed to the darker side of the mythological world constantly. So, instead of the somewhat upbeat Percy we know, he might be more withdrawn and moody.
Percy's character development would be different in several ways. Since Chiron is a centaur with vast knowledge and wisdom, Percy would be exposed to a deeper understanding of mythology and the history of the demigod world from a very young age. This could make him more cautious and less likely to jump into dangerous situations without thinking. He might also be more empathetic towards other mythical beings as Chiron would teach him about their natures and roles. Additionally, his relationship with the gods could be more complex. Instead of just being a hero who serves the gods' whims, he could have a more nuanced view and be able to question their actions based on what he has learned from Chiron.