The character known as Best Friend from the anime film Pokémon Detective Pikachu is a human woman named Emilia Christie. She works as a reporter for the television news station GNN alongside her colleague, Meiko Okamoto. Her first encounter with the main characters occurs during their investigation into the disappearance of Tim Goodman's father, Harry. She is found injured in Litwick Cave after being attacked by a wild Glalie, an event that brings her into the central mystery of the story.

As a journalist, Emilia is driven by a motivation to uncover the truth behind the strange events occurring in Ryme City, which aligns her closely with the goals of Tim and his Pikachu partner. Her professional skills and her own investigation into the source of the city's troubles make her a valuable ally. She is characterized by her resourcefulness and determination, not hesitating to venture into dangerous locations like the cave to get a story. Her role in the narrative is that of a key supporting character who provides assistance, information, and companionship to the protagonists as they navigate the complexities of the case.

Emilia forms a significant relationship with Tim Goodman, becoming his closest human friend and a trusted confidante throughout their shared adventure. Her dynamic with Detective Pikachu is also friendly and collaborative, as she respects the duo's detective abilities and works alongside them rather than against them. The German PokéWiki explicitly describes her role as becoming the best friend of both Tim Goodman and the Detective Pikachu character. Her development throughout the film is tied to the central plot; she starts as a reporter on a story and becomes an active participant in solving the mystery, proving her bravery and loyalty to her new friends. While she does not possess any supernatural abilities, her notable talent is her investigative tenacity and her skills as a broadcast journalist, which she uses to help the team uncover critical clues.