Ruri serves as the head chef at a supernatural hotel existing in perpetual twilight. A human staff member, she possesses deep blue eyes and long black hair typically styled in a side ponytail. Her petite frame makes her notably short among the hotel's inhabitants. Her work uniform consists of an orange patterned kimono beneath a frilled white apron, paired with white socks and black sandals. Her initial arrival saw her head manifest as a broken carousel, dressed in a yellow plaid dress over a black pleated shirt. In the real world, her attire reflects financial constraints: an orange "Love & Peace" top under a blue denim jacket, a long plaid skirt, black ankle socks, and orange shoes, sourced from affordable local stores.

Her personality blends responsibility, hard work, and strong will with underlying vulnerability. Maturity shaped by her background contrasts with her tendency to fluster easily, especially when teased. While she often speaks her mind or reprimands colleagues, she harbors fears of rejection, withdrawing or freezing in high-stress situations like a hostage incident. Initially, she avoids deep connections, repeatedly denying closeness with coworker Neko. Over time, she recognizes her suppression of emotions, gradually becoming more expressive about gratitude and friendship. Artist notes depict her as an ordinary girl pretending to be strong, fitting a common narrative-driven game heroine archetype.

Ruri grew up in poverty, leading to social isolation as she avoided peers to conceal her situation, fostering an aloof perception that prevented friendships. At age 14, an accident transported her to the hotel with amnesia. Upon recalling her identity, she chose to stay as staff, valuing the sense of being needed over her difficult real life. Coworker Atori's arrival shifted her motivation, sparking a desire to earn a salary for an eventual return. She later became a frequent target of Neko's teasing, developing a meaningful, though initially unacknowledged, bond.

Key events shape her story: Trauma ensued when guest Masaki Osoto held her hostage, threatening her with a knife, causing lasting fear and complete avoidance of him. Following Osoto's death and Atori's consignment to punishment, she blamed Neko for the tragedy, initially refusing to speak to her. Ultimately, she sacrificed her accumulated salary—hours representing her return time—to enable Neko's time travel mission to prevent the events, accepting Neko's promise of real-world friendship and contact details.

Departing the hotel via time travel, she attempted but failed to report Osoto to the police due to lingering fear. She wrote a letter to Neko confirming Atori's survival, beginning regular correspondence. Encouraged by her hotel experiences, she overcame social anxiety at school, befriending classmates who accommodated her financial situation. Months later, she reunited with Neko and Atori at their workplace, initially posing as Neko's social media acquaintance seeking hospitality advice. The reunion overwhelmed her, resulting in tears. She later visited Neko's home, expressing gratitude before departing.

Her relationship with Atori involves mutual respect; she views him as a protective senior figure. Developer notes suggest unacknowledged romantic feelings, though neither character addresses this. With Neko, interactions feature frequent teasing provoking angry reactions, masking deeper care revealed through her salary sacrifice and eventual emotional openness. She denied this closeness initially but later embraced it, sharing vulnerabilities and offering sincere thanks.