Futaba Ooki is a main character in the anime series 'Amanchu!'. She is a shy and introverted high school student who has recently moved to a seaside town. Through her friendship with the enthusiastic and outgoing Hikari Kohinata, Futaba becomes interested in scuba diving, which helps her come out of her shell. Over time, she gains confidence and discovers a new passion for the ocean. Futaba's journey is one of personal growth and overcoming social anxiety, making her a relatable and endearing character in the series.