Koishi Komeiji is the younger sister of Satori Komeiji, residing in the Palace of the Earth Spirits. She is a satori youkai who closed her third eye, rendering her an empty shell without a readable personality or subconscious mind. This change left her unable to perceive others' minds and made her presence undetectable on a subconscious level. She appears in Touhou games as an 'Imaginary Personality Holder' in fan works and adaptations.