Triton is often an interesting character in these fanfictions. He has his own insecurities and ambitions. Some fanfictions write him as a jealous character, feeling overshadowed by Percy. But in other well - written ones, he is shown as a complex figure who has his own reasons for his actions and eventually comes to terms with Percy. His knowledge of the sea and his relationship with Poseidon also offer a lot of potential for character development.
One interesting plotline could be a power struggle between Triton and Percy, with Poseidon caught in the middle. Maybe Triton feels threatened by Percy's newfound status as a demigod son of Poseidon and tries to undermine him.
Obviously, Percy Jackson and Poseidon are the main characters. Percy, as the demigod son of Poseidon, has his own set of powers and a complex personality. He's brave and often impulsive. Poseidon, on the other hand, is a powerful god of the sea with his own motives and a sense of fatherly love towards Percy, which is often explored in these fanfictions.
It really depends on the author. Some fanfictions in this genre can be extremely well - written, with great character development, engaging plotlines, and excellent writing style. However, others might not be as good. You won't know until you actually read it.
Annabeth is also often a prominent character in such fanfictions. As a daughter of Athena, she can act as a bridge between Percy and Athena. Her own skills and relationship with Percy add depth to the stories.
Obviously, Percy Jackson and Triton are the main characters. Percy is a demigod, son of Poseidon, with his own set of powers like controlling water and being a skilled fighter. Triton is a sea god, a son of Poseidon as well, and he has powers related to ruling the sea and its creatures.
One idea could be Percy exploring an underwater realm that only Poseidon can access. He discovers ancient secrets about his father's past and the origin of his powers. Another could be a story where Percy has to team up with Poseidon to fight a new and powerful sea - born enemy. Maybe there's a prophecy that only their combined strength can fulfill.
Definitely Harry Potter and Percy Jackson themselves. They are the main characters of their respective series, so it's natural for them to be popular in crossovers. Hermione from Harry Potter is also quite popular as she can bring her intelligence and magic skills to the crossover scenarios.
Annabeth is often a popular character. She could be in a story where she has to help Percy deal with his relationship with Poseidon. Maybe she gives him advice on how to handle Poseidon's overbearing nature or how to make the best use of the gifts Poseidon gives him.
One common theme is power discovery. Since Percy is Poseidon's son, many fanfics explore Percy finding out new powers he inherits from his father. Another theme is family bonds. They dig deeper into the father - son relationship between Percy and Poseidon which was not fully explored in the original series.
To start a 'Percy Jackson x Poseidon fanfiction', begin with a strong opening scene. Maybe it's Percy having a vivid dream about Poseidon that hints at something important. Then, introduce the main problem or adventure. You could also do some research on Greek mythology related to Poseidon to add more depth to your story. Don't forget to give Percy his characteristic personality traits like his loyalty and courage. And build up the relationship between Percy and Poseidon gradually, perhaps starting with some misunderstandings and then leading to a deeper understanding.