Unagi Nonomoto is a supporting character in the anime series 'Popotan.' She is a mysterious, white-haired girl who appears alongside her older sister, Daichi. Unagi is known for her quiet demeanor, gentle personality, and strong psychic abilities. She forms a close bond with Ai, one of the main characters. Unagi’s role is pivotal in the story, as she provides guidance and emotional support to the protagonists, helping them on their journey to discover the meaning of their existence and the nature of time.