A supporter in Hei's team. Yin is a spirit medium known as a "Doll". Very passive and speaking rarely, she is described as having no emotion and incapable of such processes (however as the series progresses she shows a slight human side with hints of emotion). Her primary function is to locate individuals, usually assassination targets, for the team as she has the ability to see anything near water when she is touching some. Yin possesses memory of Kirsi (last name unknown), who lived in Finland learning to play the piano under the tutelage of famed pianist Eelis Kostinen.