Emotionless "mediums" created to mimic the forms of humans. Dolls can form a variety of functions; the most commonly seen in the series is their use of observer spirits, which serve as reconnaissance. Dolls have different mediums through which they can send their observer spirits and must be in contact with this medium while observing; for example, Yin's medium is water, through which she can send her observer spirit anywhere else there is water. A Doll can also act as the perfect sleeper agent. It can be given the memories and personality of another person and assume a person's personality perfectly, mimicking all their habits, dreams, and feelings until the time is right. Interestingly enough, a Doll by the name of Shinoda Chiaki seemed to have some "life" of her own by saving Hei from b