Another character could be Nico. Since he has a lot of knowledge about the Underworld and the darker aspects of the Percy Jackson universe, he would be a great source of information for Percy. Nico might be initially skeptical of Percy's new role but would eventually come around to help him face any challenges that being the champion of Nyx brings.
Well, Annabeth would definitely be one. She's always been by Percy's side, and in this fanfiction, she might be a bit worried about Percy being the champion of Nyx. She could be trying to help him while also being cautious of Nyx's motives.
Grover could also be involved. He might be using his nature - sensing abilities to detect any threats to Percy that are related to Nyx's enemies. Grover could be the one to give Percy some advice on how to deal with the more otherworldly aspects of being Nyx's champion, like how to navigate the strange new powers or places that come with it.
The Titans could be antagonists. They might see Percy as a threat since he's Nyx's champion. They could try to stop him from fulfilling Nyx's tasks or even try to turn him against Nyx.
Draco Malfoy would be a likely character. Given his Slytherin status, he would likely have a complex relationship with Percy. He might start off as hostile, seeing Percy as an outsider, but then they could end up having to work together for some reason.
Definitely Annabeth. She and Percy have a strong relationship, and Hera's possessiveness would surely disrupt that. Also, other demigods at Camp Half - Blood could interact with Percy. They might sense that something is off with Percy due to Hera's actions and try to help him or at least figure out what's going on. And of course, the gods themselves might interact with Percy. Some gods might side with Hera, while others might oppose her possessiveness over a demigod like Percy.
Probably other demigods would interact with Percy. Maybe some demigods who are in need of a more stable influence in their lives would seek out Percy. Also, characters like Grover might find Percy in Hestia's care and there would be a reunion. And the gods and goddesses who are associated with the concept of home or family in Greek mythology, like Demeter, could also have interactions with Percy.
Annabeth is a very likely ally. Their relationship is so strong that she would follow him into Tartarus and be by his side through thick and thin. Grover could also be an ally. He's Percy's long - time friend and his skills as a satyr could come in handy in Tartarus. Nico di Angelo is another possibility. His knowledge of the Underworld and his powers over the dead could be useful in the dangerous Tartarus environment.
One possible plotline could be Percy having to face some new and terrifying monsters sent by Nyx's enemies. Since Nyx is a powerful figure, there would be many who oppose her, and Percy, as her champion, would be in the line of fire.
Since it's about Percy Jackson being the champion of the Pit, he's the main focus. However, in the Percy Jackson universe, his relationships are important. So Annabeth could be a major character, perhaps helping Percy strategize or solve problems in the Pit. Grover, with his knowledge of nature and the wild, might also be involved, using his skills to assist Percy. Additionally, there could be antagonists like some powerful monsters or maybe a rival champion vying for the same position or goal as Percy within the Pit.
The main character is Percy Jackson for sure. However, depending on the creativity of the fanfiction writer, there could be a whole host of other characters. We might see some ancient beings from the very origins of chaos. There could be other demigods from different cabins at Camp Half - Blood that we haven't seen much of in the original series but play important roles here. And don't forget about the villains. There could be new antagonists who are trying to either take advantage of the chaos or stop Percy from fulfilling his role as the champion of chaos. Annabeth would most likely be there to provide her intelligence and strategic thinking to Percy's more impulsive nature.
One possible plot for a 'Percy Jackson Champion of Nyx fanfic' would be that Nyx chooses Percy as her champion to stop an ancient evil that is rising. Percy would have to train in the ways of Nyx, which are very different from what he's used to. He'd have to learn to harness the power of the night, deal with Nyx's shadowy minions, and find a way to unite the demigods who are skeptical of his alliance with Nyx. As he delves deeper into this role, he uncovers secrets about Nyx's past and how it ties to the future of the demigod world.
Percy Jackson himself would obviously be a main character since it's a 'Reborn Percy Jackson Fanfiction'. His friends like Annabeth Chase are also likely to be main characters. She could play a crucial role in helping Percy adjust to his new life after being reborn. Grover would probably be there too, still being Percy's loyal friend. And the gods, especially those who have a connection to Percy like Poseidon, would also be important characters as they might have different reactions to Percy's rebirth.