The trident could give Percy new abilities. Maybe it allows him to control water in ways he couldn't before. For example, he might be able to create more complex water structures or move larger amounts of water at once. This would change how he approaches battles and challenges.
It might make Percy more confident. With the trident, he has a powerful symbol of his father's support. He could use it to face stronger enemies and gain more respect in the demigod world.
His character could change in several ways. He would have a new sense of identity. No longer just a demigod with powers, but now something more 'aquatic'. He might be more curious about his father's world and want to spend more time there. This could lead to some conflict with his human side, as he has to balance his life on land and his new underwater existence. Also, he could become more of a leader among the sea creatures, as he has a unique connection to them through the tail.
In some fanfictions, Percy might obtain the trident through a special quest. Maybe he has to prove himself worthy to an ancient sea deity who then bestows the trident upon him as a symbol of power and trust.
Well, it would make Percy's relationship with Poseidon extremely complicated. Since Amphitrite is Poseidon's wife in Greek mythology, if she's Percy's mother, it means Poseidon has a different kind of connection to Percy. Percy might feel more conflicted about his fatherly figure. He could be in a strange position where he has to navigate between the relationship with his mother and the traditional view of Poseidon as a powerful and somewhat distant god - father figure.
The trident might represent Percy's growth. It could mean that he has reached a new level in his development as a demigod, and Poseidon is acknowledging that with this gift. It's like a rite of passage in a way.
It can also make Percy more empathetic. Since he has such a powerful and protective father, he realizes the importance of protecting others too. He may be more likely to step in and help those in need, just as Poseidon does for him. This protection also gives Percy a sense of security that allows him to explore his own identity and powers more freely. He doesn't have to constantly worry about being alone or unprotected, so he can focus on growing as a hero and as a person.
In fanfictions, Poseidon often interacts with baby Percy in a very gentle and protective way. He might use his powers to create a safe environment for Percy, like a special underwater grotto where Percy can be hidden from danger. Sometimes, he sends sea creatures to watch over Percy, like dolphins or friendly sea nymphs.
Poseidon's comfort can make Percy more confident. For instance, if Poseidon tells Percy he has great potential, Percy will start to believe in himself more. This new - found confidence can lead to him taking on more challenges bravely.
In certain fanfictions, Poseidon might hurt Percy's reputation. He could do something that makes the other demigods look at Percy in a different, negative light. This could be by making decisions that seem to favor Percy too much, causing jealousy among others, or by getting Percy involved in some political mess within the godly realm that Percy has no control over. This can lead to Percy being ostracized or having to deal with a lot of unnecessary drama and pain.
In some versions, Poseidon might keep Percy's mother at a distance to protect her from the wrath of the other gods. He could send her gifts secretly to let her know that Percy is okay. For example, he might send a magical seashell that can communicate with Percy.
Poseidon's possessiveness can also shape Percy's view of relationships. He might become more cautious about getting too close to others or letting them have too much influence over him. Since his father is so possessive, Percy could be afraid of losing his freedom in other relationships. At the same time, he might also learn to value true friendship and loyalty more, as those are things that can't be controlled by Poseidon's possessiveness.