In some fanfiction, Percy could seem cold - hearted because the writer is trying to tell a story from a different perspective. For example, if the story is told from the point of view of someone who doesn't understand Percy's motives. Also, it could be a way to add an element of mystery or make Percy a more complex character. However, this often goes against the essence of who Percy is in the official stories, where he is generally a very empathetic and caring person.
Sometimes, it might be to explore a different side of his character. If the fanfiction is set in a more dystopian or harsh world, the writer could make Percy cold - hearted as a survival mechanism. He might have to be more cut - throat to deal with the new threats. But this is a far cry from his original character.
One reason could be that the writer wants to create conflict. By making Percy cold - hearted, they can set up situations where he has to overcome this new trait. Maybe it's a way to show how much he's changed due to some extreme event in the fanfiction's plot.
In some fanfiction, Percy might be depicted as cold - hearted, but it's often a departure from his canon character. Fanfic writers may do this for creative or plot - driven reasons. However, the real Percy is known for his loyalty and big heart.
The unpredictable plot. One minute Percy could be at Camp Half - Blood training, and the next he's thrown into a life - threatening quest. That's chaos.
The use of Greek mythology makes it seem so. It's like taking the old and making it new. Just as fanfiction does with existing works.
The fact that Percy is the son of Poseidon gives the story a hydrokinetic feel. Since Poseidon is the god of the sea, Percy inherits powerful water - based abilities. Throughout the series, we see him use these abilities constantly, whether it's to fight monsters or solve problems. This heavy focus on water - manipulation is what can make it seem like a hydrokinetics fanfic.
There's really no valid reason for it to seem like Percy Jackson is Robin fanfiction as they are two completely different things. But perhaps some people who are not very familiar with either might make a wrong assumption just because they are both part of the realm of fictional stories. However, once you look into the details of each, it becomes clear that they have no relation.
A love interest who breaks his heart multiple times. For example, if this person plays with his feelings, lies to him, or cheats on him, Percy could become cold - hearted as a form of self - protection. He would no longer trust easily and would close his heart to new relationships.
There are fanfictions where Percy's powers are affected by the cold. Maybe his control over water becomes difficult as it freezes too quickly in the extreme cold. A really interesting one could be a story where he has to team up with a cold - natured deity, like Khione, to save the world from a super - cold apocalypse.
In fanfic, a tragic backstory that was different from his original one could lead to Naruto being cold - hearted. Maybe if he had been abandoned by the whole village instead of just being shunned by some, he could grow up bitter and cold. Also, if he had to make really tough decisions that cost him a lot, like sacrificing friends for the greater good in the fanfic world, it might harden his heart.
Good Percy Jackson fanfiction usually has an engaging plot. It could be a new adventure that fits within the world of Percy Jackson, like a new quest that ties in with the mythology in the books. It also might have interesting twists on the relationships between the characters, such as a different take on Percy and Annabeth's relationship.
In fanfiction, his knowledge of different mythologies can be greatly expanded, making him seem like a genius. For instance, he could have an encyclopedic knowledge of not just Greek, but also Roman, Norse, and Egyptian mythologies, which helps him in unexpected ways during his adventures.