Some original characters are antagonists. They could be a powerful demigod gone bad or a new creature with abilities that pose a great threat to Percy and his friends. These characters are popular because they create conflict and tension in the fanfiction. For example, a demigod who has the power to manipulate time and uses it to try and rewrite history to suit his own evil plans.
One popular original character is the 'Shadow Demigod'. This character often has the ability to blend into the shadows and cause chaos in Camp Half - Blood. Another is the 'Dark Oracle' who gives cryptic and often harmful prophecies. There's also the 'Soul - Eater', a creature that preys on the souls of demigods when they are at their weakest.
One popular original character is often a new demigod who is related to Percy's family in some way. For example, a cousin who has a unique power that helps Percy and his family in their battles. This character adds a fresh perspective to the family's adventures.
Percy himself is obviously very popular. After all, it's his series. Annabeth is also a fan favorite, as her intelligence and strong will make for interesting storylines. Nico di Angelo is quite popular too, especially when his powers and his somewhat dark nature are explored in fanfiction.
One popular original character could be a young girl who is a seer. She has visions not only of the present battle but also of the future implications. Her visions guide Percy and his friends in making strategic decisions during the Battle of Manhattan, like when to attack and when to retreat, and she also warns them about hidden traps and ambushes.
One popular original character is often a new demigod with a unique power. For instance, a demigod who can control time on a small scale, which comes in handy during battles and tricky situations. They add a fresh element to the existing world of Percy Jackson.
Percy Jackson himself is often very popular. His powers over water and his heroic nature make him a central figure in many fanfictions.
Annabeth Chase is also a fan favorite. Her intelligence and strong will make her a great character to explore in fanfiction. Writers might focus on her architectural projects in the context of the demigod world, or her relationship with Percy from different angles.
Grover is another character that gets a lot of love in fanfiction. His kind - hearted nature and his connection to nature make for interesting storylines. For example, a fanfiction could focus on Grover's role in protecting a new and endangered species of magical creature, and how Percy and Annabeth help him in this mission.
Percy Jackson himself is extremely popular as he is the main character of the original series. Fans love to write about his interactions with Aphrodite. Aphrodite is also a popular character in these fanfictions as she brings the element of love and beauty. Annabeth Chase often appears as well, especially in plotlines where Aphrodite's actions might interfere with Percy and Annabeth's relationship. Grover could also be a character that shows up, usually as Percy's supportive friend during the events that are set in motion by Aphrodite - related fanfiction plots.
Grover often appears in these fanfictions too. His loyalty to Percy and his own unique abilities as a satyr add an interesting dynamic. He could be the one who senses the presence of other mythical creatures in the school and alerts Percy and Annabeth.