She is Rea Sanka's biological mother. Dan'ichirō Sanka proposed to her when she was 15 years old, having met her after a fencing match. Since she was frail, she died soon after giving birth to Rea. She has not been named, and is referred to as "that girl" by Aria Sanka.
She looked just like her daughter, with straight black hair, dark blue eyes, and fair skin. She wore her hair in a short hime cut style with a white flower on one side, and was wheelchair-bound.
Although her personality was not covered in-depth in the series, she seemed to be a calm, polite, and sweet girl. She also appeared to be rather wise for her age.