The main character is Percy. In relation to his status as a middle child, his parents also become important characters in the fanfiction. Their parenting style and the attention (or lack of it) they give to Percy compared to his siblings can be a major plot point. And then there are his peers at school or in the neighborhood. Some of them might be friends who stand by Percy, while others could be rivals. All these characters together create the world of the percy the middle child fanfiction.
In many 'child of pan percy jackson fanfiction', Chiron, the centaur, can be an important character. He is very knowledgeable about the demigod world and can offer guidance to the child of Pan. Additionally, there could be new characters created specifically for the fanfiction, like a mysterious nymph who has a special connection to the child of Pan and helps them uncover their true destiny within the world of Percy Jackson.
Maybe the child of one of Percy's friends from Camp Half - Blood could also be a main character. For instance, the son or daughter of Grover. They could have unique abilities related to nature and prophecy, and bring a different perspective to the story compared to Percy's kids.
Obviously, Percy Jackson would be one of the main characters since it's about him being the true child of chaos. There might also be other characters from the original Percy Jackson series like Annabeth Chase, who could play an important role in his journey as his girlfriend and a smart strategist. Grover Underwood might also be there as Percy's friend and protector.
One interesting story could be Percy's struggle to find his own identity among his siblings. Since he's the middle child, he might feel overshadowed at times. In some fanfictions, he discovers a unique talent that sets him apart.
Percy is the central figure, no doubt. But also, there could be other characters like Grover. Grover would be in a difficult position as Percy's friend. He would want to support Percy but also be cautious because of Percy's connection to Kronos. Additionally, some new characters might be introduced, perhaps other children of Kronos or characters from Kronos' past who have a role to play in Percy's story.
Since it's a Percy - centered fanfic, Percy is surely one of the main characters. There may also be other characters from the Percy Jackson series like Annabeth, Grover, etc. who could be involved in the story to react to Percy's new identity as a child of Chaos.
A new character could be a transfer student from another demigod camp. This student has a different set of powers and a unique backstory related to a less - known Greek god. They could initially clash with Percy but then become great friends as they face challenges together.
The child could be an orphan from a far - off land that Percy visited. Maybe Percy found the child alone and starving, and felt responsible for the child's well - being, so he brought the child back.
I'm not sure specifically since I don't know the exact fanfiction, but it could be his friends who might be either involved in his hacking activities or completely unaware of them. Maybe there's a mentor - like figure who guides him in the world of hacking.
The child could be a prophesied one. In the world of Percy Jackson, prophecies are common. So, this child could be the one foretold in some ancient prophecy that is linked to Tartarus. Percy finding the child sets off a chain of events that will either save or doom the world. Maybe the child is the key to closing a portal in Tartarus that is releasing evil into the mortal world, and Percy is the only one who can help the child fulfill this great task.