Yamata-no-Orochi

The Yamata-no-Orochi (八岐大蛇, Great Serpent of the Eight Forked Roads) was a creature which once existed in the Human World in earlier times. It brought about dark times and was known for consuming humans before it's banishing to the Beast Realm at the hands of the gods. Eventually the creature would be slain and put to rest, being reduced to nothing but it's scales which still hold it's spiritual energy. Shinmyousuke Hikage, a scientist of the Twelfth Division would obtain these scales and create a series of artificial souls which could serve as perfected reincarnations of the deceased Yamata-no-Orochi.