Based on her family's well-regarded koji and fermented goods shop, Ryoko Sakaki gained early exposure to fermentation techniques. She earned acceptance into Tōtsuki Culinary Academy's middle school section and later secured residency at Polar Star Dormitory. There, she formed close friendships with fellow 92nd Generation students Yūki Yoshino and Megumi Tadokoro, often practicing cooking together before advancing to the high school division. Ryoko possesses waist-length fuchsia hair with split bangs reaching her chest, orange eyes, and a slender figure. She wears the standard Tōtsuki seasonal uniform and a pure white chef's uniform while cooking. Four months after the Régiment de Cuisine, she cut her hair to a chin-length bob. Her demeanor is gentle, kind, and notably level-headed compared to other dorm members. She frequently comforts others, particularly Yūki Yoshino, serving as a "big sister" figure within the dormitory. As a first-year, Ryoko participated in the Tōtsuki Friendship and Rapport Training Camp. She witnessed the announcement of the camp's rigorous challenges alongside other Polar Star residents and supported Megumi Tadokoro during moments of self-doubt. Ryoko passed all challenges, including the demanding breakfast buffet assignment requiring an original egg dish for 200 guests, expressing relief when all Polar Star first-years survived. Selected as one of the 60 participants for the 43rd Annual Tōtsuki Autumn Election, her inclusion was announced alongside Yūki Yoshino's, prompting an excited celebration. During the preliminary round, she crafted "Soy Natto Curry Rice," utilizing black koji and fermented soy natto instead of pulses. Judges initially noted its plain appearance but praised its complex flavors and sticky texture. Fermentation expertise defines Ryoko's culinary identity. She maintains a dedicated workshop near Polar Star Dormitory for fermenting ingredients, producing fermented rice juice consumed at dormitory gatherings. She assisted Sōma Yukihira by teaching him fermentation techniques to enhance mackerel for an Autumn Election dish. Following the Régiment de Cuisine and Azami Nakamura's defeat, Ryoko continued her studies at Tōtsuki. Her relationships within Polar Star Dormitory remain strong, characterized by mutual respect and camaraderie.