Noriko Nijō attends Lillian Girls' Academy, a Catholic school, an unexpected outcome driven by her deep fascination with Buddhist statues and art. This background subjects her to constant cultural whiplash as she confronts the school's traditions, including its antique uniforms and refined student mannerisms, which she struggles to adopt. Her detachment manifests in informal language; privately, she calls Shimako Tōdō "Shimako-san" instead of the required respectful "Shimako-sama" and frequently avoids polite Japanese speech.

She presents a calm exterior masking a straightforward and occasionally fierce temper. This internal contrast is mirrored externally by her traditional Japanese doll-like appearance, marked by plain, jet-black hair, a stark counterpoint to Shimako's Western doll aesthetic. Noriko develops a close bond with Shimako Tōdō, becoming her petite sœur during Shimako's second year, formally entwining their paths within the academy's sœur system.

Beyond her connection to Shimako, Noriko forges a meaningful friendship with Tōko Matsudaira and cares deeply for both individuals. Her interactions and relationships aid her integration into the school's social world, yet her initial cultural dissonance remains a defining trait. Noriko's journey focuses on slowly finding her footing within Lillian's environment while holding fast to her distinct identity and passions.