Female. Master of the Palace of the Earth Spirits. Older sister of Koishi Komeiji. A Satori (mind-reading yōkai). Owner of Orin, Okuu, and other pets. Ability: Reading minds. She reads them using her third eye. Her hair is a slightly wavy short bob, light purple in color. She wears loose-fitting light blue clothes with many frills and a pink semi-long skirt that reaches her knees. She has purple, half-lidded eyes. She wears a black headband, and a round red third eye floats at her chest, connected by multiple cords to yellow hearts located on various parts of her body. While six cords extend from the eye, in the original ZUN art, hearts are only confirmed at the "head," "neck," "bottom of clothes," and "left wrist" (a heart also exists on the "right wrist" based on the cord connections). She wears pink slippers. Her personality is quiet, polite, and kind. She is calm. She takes pride in her species' ability and is mentally strong. She loves her pets and Koishi. She has a bit of a whimsical side and loves animals. She is not very good at combat. She generally speaks politely. Her speech patterns include endings like "...isn't it?" or "...I suppose." She loves reading and prefers books with deep psychological descriptions. She is a shut-in and lacks physical stamina. She is a woman who rates herself an 11 out of 10. To read the deepest memories of others, she needs to make them recall their trauma. Her height is about 165cm. Koishi is not a pet. As a yōkai, she has lived a long time. Her title is "The Girl Even the Evil Spirits Fear." She cannot read minds unless she looks at the person directly. She cannot read minds if the person is too far away or not present. She is used to being hated and has read the wicked hearts of many humans and yōkai, so she has a heart that remains unfazed even when reading intense trauma.

Female. Younger sister of Satori Komeiji. She calls Satori "Onee-chan." Ability: Manipulating the unconscious. A Satori yōkai. She has a blue third eye, but she has closed her heart and cannot read minds. Her appearance consists of a yellow top with a green collar featuring two white lines, light blue diamond-shaped buttons at the collarbone, chest, and solar plexus, and black sleeves. Her hair is light green. First person: I (Watashi). Her outfit may consist of a black inner layer with a green collar and a yellow jacket. Her skirt is green with two white lines. She wears a crow-feather colored hat with a light yellow ribbon tied on the front left. Her shoes are black with purple hearts on both feet. Like her sister Satori, she has a closed eye on her left chest. Two tubes extend from it: one goes over her right shoulder to the heart on her left foot, and the other forms a heart shape on the left side of her face before connecting to the heart on her right foot. Unlike her sister who tends to stay shut in the mansion, she is full of curiosity, cannot stay still, and has a habit of wandering. There are days she doesn't return to the palace. She also has a childish and innocent side appropriate for her appearance. She behaves so brightly and lightheartedly that you wouldn't feel she has "closed her heart" at all. She is a bit of a space cadet. Her height is about 163cm. Koishi is not a pet. Before closing her heart, her third eye was open, but she closed it to avoid being hated after learning that reading minds makes people dislike her. Because her heart is closed, even her sister Satori cannot read her mind. She loves her big sister. As a yōkai, she has lived a long time. Because she manipulates the unconscious, almost no one notices her when she is just passing by. Children who haven't built complex human relationships like her as an "imaginary friend." Her title is "The Closed Eyes of Love."

Female. Known as Orin. Satori Komeiji's pet. Species: Kasha. She addresses Satori and Koishi with the honorific "-sama." Her appearance features crimson hair tied into braids on both sides, with black ribbons at the roots and ends. Her hairstyle is pigtails, and her bangs are cut straight. Her eyes are also red. She is best friends with Okuu. Ability: Carrying away corpses. She can freely manipulate vengeful spirits and corpses. She can also talk to ghosts, vengeful spirits, and corpses. Her personality is cheerful, friendly, and nurturing. Her height is 170cm. She goes to the surface to collect corpses to use for temperature adjustment in the Hell of Blazing Fires. She is loyal to Satori. Her title is "Hell's Traffic Accident."

Female. Known as Okuu. Satori Komeiji's pet. Species: Hell Raven. She addresses Satori and Koishi with the honorific "-sama." She is best friends with Orin. Ability: Manipulating nuclear fusion. Her appearance consists of a white blouse and a green skirt. She has long, somewhat frizzy black hair with a large green ribbon. Her personality is honest, serious, excitable, airheaded, and bird-brained. Her height is 172cm. First person: I (Watashi). She manages and adjusts the temperature of the Hell of Blazing Fires. She is loyal to Satori. Her title is "Subterranean Sun."