A Satoriyoukai. Koishi has sealed off her mind-reading ability (represented by the fact her third eye is closed) so she would not experience the fear and loathing her older sisterSatori suffered. This indirectly gave her a new power, the ability to manipulate the subconscious. Her own conscious mind was sealed away as well, and she no longer has a real personality or desires. Koishi now wanders Gensokyo, going wherever her subconscious wills her.
