Summary
Yin serves as a member of Hei’s team, functioning as an emotionless spirit medium referred to as a "doll." Her abilities center on tracking and observation through water, though these powers are only active when she maintains direct physical contact with it. Initially, Huang claims that her "program" is minimal, rendering her incapable of emotion or independent decision-making. However, she disproves this limitation when she actively chooses to remain with Hei and the others rather than leaving. Details regarding her past suggest she suffers from poor eyesight or near-blindness, as evidenced by her inability to perceive if the moon was full or if her teacher had retrieved his dropped pen. Yet, this apparent disability is contradicted by moments where she demonstrates perception beyond what is visibly apparent. Very little is known about her transformation into the "doll" medium, though it appears linked to a personal tragedy. There are indications of romantic feelings for Hei, a sentiment highlighted when Amber notes their similarities in this regard and asks Yin to look after him. As the series progresses, Yin begins to exhibit genuine emotions and independent will. She decides to stay as Hei’s partner, noticing changes in his behavior without being instructed to do so. Her attachment becomes most evident when she calls Hei back from the void, refusing to let him abandon her alone. During this development, her observation apparition evolves, gaining a human-like body shaped in her silhouette and acquiring the ability to make physical contact.
