Luna Carson is a supporting character who appears in the Pokémon special Mewtwo Returns. She is a Pokémon researcher and lives at the Purity Canyon rest stop lodge, where she also serves as an overseer and a part-time worker for a local bus company. She is the younger sister of Luka Carson. Luna dedicates herself to studying Pokémon habitats in the area around Mount Quena, and she helps tourists who pass through Purity Canyon, often offering them lodging and advice.

Her personality is warm, hospitable, and knowledgeable about the local terrain and wildlife. When Ash, Misty, and Brock miss the monthly bus, Luna invites them to her lodge, provides them with refreshing spring water, and suggests they take a boat down the Purity River to continue their journey. She demonstrates a strong sense of responsibility toward the natural environment, particularly the pure water that originates on Mount Quena. She fears that if people discover the water's healing properties, they might flock to the area and inadvertently destroy it. This concern drives her to work alongside the researcher Cullen Calix, also known as Benishirina, to study the water and protect the habitat.

Later in the story, after Team Rocket steals Pikachu, Luna accompanies Ash and his friends through a severe storm up Mount Quena, using her intimate knowledge of the region to guide them. She proves resourceful when she helps construct a makeshift canoe from a fallen log so they can cross the lake to reach the island where Pikachu has been taken. Throughout the ordeal, she remains calm, practical, and supportive.

Luna develops a close working relationship with Cullen Calix, and by the end of the special the two share a mutual romantic interest, deciding to remain at Purity Canyon together to continue their research. She does not possess any special powers or battle abilities, but her expertise in Pokémon habitat research, her familiarity with Mount Quena, and her caring, determined nature make her an important guide for the main characters.