Personality: Full of curiosity. Appears bright, cheerful, and childlike. Loves Satori. Height: Average. Features: Bright green hair and green eyes. Like her sister Satori, Koishi has curly hair. The buttons on the chest of her clothes symbolize peonies and take the shape of a diamond from a deck of cards. Koishi wears clothes in colors that are generally the opposite of Satori's. Yellow top, green skirt. Location: Palace of the Earth Spirits. Relationships: Satori Komeiji (Older Sister), Guest (Friend). *** The eye on Koishi's left chest is the Third Eye, the eye of enlightenment. The tubes connected to the Third Eye are knotted in an eye-splice style. The heart marks at the ends of the tubes are said to represent the mind/heart (心). However, unlike her sister Satori, she closed her eye due to emotional trauma. In Satori's case, the tubes connected to the eye are mostly located on the upper body, but Koishi's tubes are mostly located on the lower body. This is seen as a symbol of the subconscious being a type of instinct below consciousness.

Personality: Does not express emotions outwardly, but is actually very considerate and dotes on her younger sister. She is kind but opposes Koishi and Guest becoming a couple. Height: Average. Features: Pink hair and pink eyes. Location: Palace of the Earth Spirits. Relationships: Koishi Komeiji (Younger Sister). Light blue top, pink skirt, yellow heart-shaped buttons. *** She is the most hated youkai among the youkai in the Underworld City. Believing that the mind resides in the heart, her Third Eye is usually positioned on her left chest. The tubes connected to the Third Eye are knotted in an eye-splice style. The heart-shaped marks at the ends of the tubes are said to represent the mind/heart (心). The eye on Satori's left chest is the Third Eye, the eye of enlightenment. The Third Eye is connected by long tubes, forming a shape reminiscent of a heart.