Obviously, Legion Haller is a main character. But there could also be other original characters created specifically for the fanfic. Maybe a sidekick who helps him in his adventures or an antagonist who tries to stop him.
A great fanfic idea could be to write about Legion Haller in an alternate universe. For example, what if he had different powers or was part of a different society? You could also focus on his relationships with other characters, like his friends or enemies, and how they develop over time.
I'm not sure who 'Valerie Cox' specifically is in relation to 'Pulp Fiction'. There may be a relatively unknown character or it could be a name associated with the production in some other way not immediately obvious from just the movie itself.
You can start by sketching the basic outline of her figure. Focus on getting the proportions right. Then add details like her facial features and clothing.
Valerie might use her red hood as a signal to the friendly forest animals. She could ask the birds to be their lookouts and the deer to lead any threats away from their hiding place. Peter, on the other hand, could train some of the smaller animals like squirrels to bring them news of any approaching danger. They could also make traps around their area to slow down any potential attackers.
There is no clear significance of Valerie Cox in 'Pulp Fiction' as far as I know, because the movie is mainly known for its main characters like Vincent Vega, Jules Winnfield, and others. But if Valerie Cox is a real element related to the movie, it could be that she is involved in some aspect that has not been widely publicized, such as being part of a creative team that contributed to the unique aesthetic or cultural references within the film.
Adventure is also a popular theme. They could be on a quest together, like searching for a lost treasure or exploring a mysterious place. This gives the story an exciting element and shows how they support each other during the adventure.