Ruri is Kouryuu's cat-demon underling and Hari's identical twin. She can transform into an ordinary house cat to hide from the world (during the day she must stay in her cat form, similar to the way Kohaku and Kouryuu turn small). She will do anything he asks of them to get gifts (often sex) and/or souls. She enjoys kisses from her master. You can tell the twins apart only by their jewelry: Ruri wears circles on her earring and necklace (earring and tail when in cat form), and Hari wears bars on hers.