Ritsuko is an adult woman. She has a short black hair, turquoise eyes, and a mole on her right chin, below her lips. She wears a short, purple dress with flower motif, white cardigan, large thin gold hoop earrings, a gold heart necklace, and lilac flat shoes with violet flower decorations. She carries a DSLR camera with its strap worn over her right shoulder.
Ritsuko is a 38 year old press photographer who has a dominating personality. She was the first survivor to meet Ayame Itou. Ritsuko exchanges text messages with her fiancé, Masami Yoshinaka, who works at the Amare Patriarcha Crucis hospital, while dreaming of being reunited. She persuades the others survivors to gather and barricade themselves at the nurse's station, however... 
Ritsuko makes her first appearance after shining her flashlight at a woman in red who was attacking Ayame. She then tells Ayame how she ended up in the hospital and that she witnessed the aftermath of a mother throwing her own child down from the third floor of the hospital and then jumped off herself, thus killing both of them instantly. While everyone ran away, Ritsuko decided to take a picture of the incident. Strangely enough, the child started to rise up and scream. While stunned, Ritsuko was knocked unconscious from behind by an armed SWAT member.
As the two decide to explore the hospital together, they meet and save Chiyomi Homura on the way. During a heated argument, however, Ritsuko drives Chiyomi away. As she and Ayame continue exploring the hospital, they eventually find Ryuji Shimazaki and Curara Teshimizu. On their way out, they are captured by an onslaught of heavily armed SWAT members. The mastermind behind the attack turns out to be Masami. He proceeds to punch Ritsuko and lifts Ayame's shirt, revealing an empty hole in her chest.