Misty Springfield is the main protagonist of the anime Kasumin. She is a fourth-grade student whose parents are zoologists who travel to Africa to conduct research. To see them off and stay while they are away, she moves to Kasumi Town. There, she takes up residence in a large, mysterious mansion surrounded by forest. This mansion is the home of the Kasumi family, also known as the Mistins, who belong to a race of magical creatures called Henamon. Many of these Henamon appear as talking household appliances. In exchange for her room and board, Misty takes on the responsibility of managing the household chores, including cooking, cleaning, and laundry.

Misty is a cheerful, confident, and outspoken girl who possesses a level of mental maturity beyond her years. She is resilient and responsible, quickly adapting to the chaotic and whimsical nature of her new home. Despite the strangeness of living with a family of magical beings, she remains caring and becomes a stabilizing presence in the household, often acting as the glue that holds the eccentric group together. Her primary motivation is to adjust to her new living situation and maintain a sense of normalcy while her parents are away. Over the course of the story, she navigates the comedic and magical situations that arise from her daily life with the Henamon, gradually finding a sense of belonging in this bizarre yet loving environment. Her role in the story is that of the central character through whose eyes the audience experiences the fantastical world of the Kasumi mansion. Her key relationships are with the members of the Kasumi family and the various Henamon creatures that live there, with whom she forms a close, found-family bond. Her notable abilities include her resourcefulness in managing the household and her remarkable adaptability in the face of the supernatural incidents that occur around her. Throughout the series, she grows from a temporary guest into a beloved and integral member of the household.