Kuroneko is a mysterious black cat that can at will been seen or unseen and also be incorporeal. It always seems to be around Kagami Ouri, and he seems to be the only person the cat talks to. It shows up at moments that involve the shikabane and shikabane hime and gives Ouri clues about them. The intention of whether it is friend or foe is unknown. The cat is identical to a pet that Ouri cherished as a child, which died after being run over by a vehicle. Soon afterwards, this cat appeared.
Near the end of the series, the cat revealed its true nature with the help of a foe shikabane who was once a fellow orphan along with Oori. In fact, they all are. The cat was made up of a number of children who Oori's mother (shikabane) had kidnapped trying to fulfill her attachment to this world: to hold her child in her hands. Later, the cat engulfed Oori in a monstrous form, only to help him in the end later, disappearing without a trace.