Ryoko Sakaki attends Totsuki Culinary Institute as a second-year high school student in the 92nd generation. Her family's renowned koji and fermented goods shop provided an early foundation in fermentation techniques, leading her to specialize in fermented foods like shio koji. She maintains a dedicated fermentation workshop near the Polar Star Dormitory where she lives. She possesses distinctive fuchsia or purple hair and matching eyes. Her hair was initially waist-length but was later cut to a chin-length bob following the Régiment de Cuisine. She has a slender figure and typically wears the standard Totsuki uniform or chef's attire while cooking. Her personality is characterized by calmness and maturity, making her a stabilizing presence within the dormitory. She frequently acts as a "big sister" figure, supporting and comforting others such as friends Yuki Yoshino and Megumi Tadokoro. This supportive role is evident in group settings, like the Totsuki Friendship and Rapport Training Camp where she encouraged Megumi through self-doubt and helped manage the stress of rigorous assignments. Her level-headedness contrasts with the dorm's more eccentric personalities. Her involvement in key events includes attending the 92nd Generation Orientation Ceremony, witnessing speeches by Senzaemon Nakiri and Soma Yukihira. She participated in welcoming Soma to Polar Star Dormitory and observed his early cooking duel against Satoshi Isshiki. During the Training Camp, she completed challenging tasks like preparing 50 meals after an exhausting first day and passing the surprise breakfast buffet challenge requiring an egg dish service. She also qualified for the 43rd Totsuki Autumn Election alongside Yuki Yoshino, celebrating their selection with fellow dorm residents. Her culinary development centers on fermentation, leveraging techniques inherited from her family's expertise. Her foundational role within the dormitory and consistent focus on fermentation define her trajectory.