Kirie possesses an uncanny resemblance to Yuuko, although Kirie has her hair much shorter than Yuuko's. She also has an athletic physical build, although she is insecure to Yuuko's comparatively large breasts.
Initially, Kirie shows a tomboyish behavior, showing off a confident attitude that is not swayed by the opinions of others. However, her tough facade can be easily torn down when she encounters frightening things. This side of her is much more vulnerable than her more confident side, but she manages to gain the respect of others, including Momoe Okonogi's, nonetheless. She is also jealous of Yuuko and how Teiichi treats her, she will often think about growing her hair long, which makes her look like Yuuko. It is unknown if Yuuko fails to acknowledge Kirie because of Kirie's own doing.
Kirie meets up with Teiichi to warn him about the ghost of Seikyou Academy, and she tells him of the story of "Spirited Away", which tells of a ghost who takes away the hearts of people whom it interacts with. She then reveals her intentions to save Teiichi from Yuuko after seeing her "true form" and believing that no spirit will do no harm to the living.
Although she was successful in influencing how Teiichi sees Yuuko, Kirie's plan was foiled and her vulnerable side is exposed when she tried to explore the room where Yuuko's remains are. Kirie also discovers that what she believed in were warped truths, and apologizes to Teiichi before leaving. Unknown to Yuuko and Teiichi, Kirie encountered something more grisly than Yuuko's "true" form on her way out.