Percy is the obvious main character. There could be his friends from previous adventures who accompany him to the camp. Additionally, there might be a villain in the story who is misusing the fish blood. This villain would be an important character as they would drive the conflict in the fanfiction. There could also be some local creatures at the camp that are affected by the fish blood and they could be important characters as well.
Well, in this fanfiction, perhaps Percy goes to the camp and has to deal with some sort of danger that is related to the fish blood. It could be that there is a curse on the camp that is activated by the fish blood, and Percy has to find a way to break it. He might meet new friends or face old enemies during this adventure at the camp.
Some of the Roman gods or goddesses might also play important roles as characters. They could interact with Percy in different ways compared to how they interact with the Roman demigods in the camp. For instance, if Jupiter shows up, he might have different expectations of Percy compared to Poseidon, Percy's father in Greek mythology.
He could meet some of the older campers who usually don't interact with the new arrivals right away. They might give him some special advice or warnings about the camp.
I think Tyson would be an excellent character to include. He's Percy's half - brother and his strength as a Cyclops could be very useful in various situations. His innocence and loyalty also make him a lovable character. Additionally, Clarisse could be paired with them. She has a tough exterior but deep down she's a strong and capable demigod. Her rivalry - turned - friendship with Percy could add some spice to the fanfiction. And of course, Chiron, the centaur, could be involved. His wisdom and guidance are always valuable and could play a crucial role in their adventures.
In this fanfiction, Percy is the main one in control. But characters like Chiron, the centaur mentor, would also play a significant role. Chiron has a wealth of knowledge and experience, and Percy would likely rely on him for advice on matters of the camp's history and traditions. Also, there could be some antagonist characters within the camp who don't like Percy's new rules and ways of controlling, which would add some conflict and drama to the story.
Obviously, Percy would be the central character. His friends like Annabeth, Grover, and other demigods from Camp Half - Blood might also be important. They could be trying to help Percy or might be affected by his insanity. For instance, Annabeth might be desperately searching for a way to bring Percy back to his senses.
Obviously, Froggy is one of the main characters. There might also be other animal friends who go to the camp with Froggy.
Obviously, Percy Jackson himself would be a main character. Since it's about him being in a god camp. Annabeth Chase is also likely to be a main character as she has always been an important part of Percy's life. Grover, Percy's best friend, would probably be there too. And there might be some new characters, like other god - like beings or powerful demigods in the camp that Percy interacts with.
It's likely that Chiron, the centaur, is also a main character. He has a wealth of knowledge and experience and can guide Percy and the other demigods in using their powers effectively to protect the camp. He might also be involved in training them and preparing for different types of threats that Percy's powers need to counter.
The betrayal of Percy by Camp Half - Blood in fanfiction can also be a way to show Percy's growth and resilience. He has to face the ones he considered family turning against him. This can lead to some really interesting character development arcs, where Percy has to re - evaluate his loyalties and find new allies or even learn to rely more on his own strength.