Yonaka has fair skin, black eyes with white pupils, and black hair with braided pigtails. Her bangs cover her right eye. She wears a typical Japanese high school uniform consisting of a white dress shirt, a red plaid ribbon, a gray blazer with two brown buttons, a red plaid pleated skirt, dark gray stockings, and black loafers. Yonaka's brother Shinya seems to have left her and their family when she was in junior high. Several years seem to have passed since the two had seen each other.