Yanagi is a teenage girl gifted with the innate ability to heal any kind of physical injury, and Recca immediately offered to serve her as his loyal ninja after seeing her compassion when she healed a severely injured puppy in a local park (in the anime series, she heals Recca after a pile of metal pipes collapsed on top of him). She falls in love with Recca, but is to naive to see it. She also is the prime objective of the series' main antagonist, Mori Koran, as he believes that her healing powers will help him attain eternal life.