Kagami is a tsukumogami, a spirit inhabiting a mirror who gained physical form. She resides in the Nagatsuki household alongside other tsukumogami, serving and protecting Botan Nagatsuki. Kagami appears as a young girl and possesses a lively, open, and emotionally expressive personality. She readily displays her reactions, including fear or apologies during conflicts. She uses specific honorifics, addressing Hyoma Kunato as "Mr." and Haori and Yu with "chan." Kagami has a fondness for sweet beverages, especially Kahlua milk. Initially, Kagami feared Hyoma due to his harsh, hostile treatment of tsukumogami, stemming from his traumatic past. However, after being attacked by the spirit Yagen during a special review and subsequently rescued by Hyoma, her fear shifted. She developed a friendly attitude and genuine liking towards him. As a mirror tsukumogami, Kagami wields the supernatural "Truth Revealing Mirror" ability. This power allows her to perceive truths about individuals' pasts or the inherent nature of objects and events. Activating it causes a circular mirror to materialize on her forehead. The ability functions defensively, centered on reflection and revelation. Her role in the household and her relationships contribute to the broader dynamics of human and spirit coexistence.