Kirin

The Kirin is a black-wolf from Naraku who acts as Byakuei's opposite, it emits a large amount of miasma and is extremely violent. It is revealed in chapter 52 to be the incarnation of the Kyuubi. In the final battle, Kirin burst through Byakuei and snapped the chain that binded Kagura's soul to Byakuei. If the chain were snapped, it is like tearing your soul in half. Kagura was later saved by Yomi when she used her remaining soul to seal the gap in Kagura's. Kirin was killed after one of the Black Priestess's guardians reached down its throat and tore out its black heart.