Mitsuko has dark purple hair that is styled in a bowl cut reaching the height of her chin with a longer bang on the left side of her face just long enough to touch her shoulder. Back in her Aihara Academy days, she had longer hair that she kept in a ponytail.
Mitsuko bears resemblance to Harumi as they both are really tall and they have large breasts.
Mitsuko is a cold and serious person, similar to Mei. However, unlike Mei who can be concessive, Mitsuko firmly believes that the school's rules should be kept at all costs. According to Harumi, during Mitsuko's time as the student council president, she ruled the school with an iron hand. However, she is capable of being kind to certain individuals.
- The name Mitsuko can have different meanings depending on the writing, such as 光子 ("shining child"?) or 睦子 ("harmonious child"?). Mitsuko's name, however, has no actual meaning as it's written in Hiragana, although "子" is the kanji for "child". "Taniguchi" (谷口?) means "mouth of a valley".
- Based on Harumi's description, Yuzu imagined Mitsuko as a Harumi look-a-like dressed like a stereotypical Japanese delinquent and holding a club with nails running through it.