八岐大蛇
After the sword's owner, Susanoo, was banished from heaven by the reason of killing one of Amaterasu's Attendants and destroying her rice fields, he descended to the Province of Izumo where he met Ashinazuchi, an elderly man who told him that the Yamata no Orochi ("Eight-Branched Serpent"), who had consumed seven of his eight daughters, was coming soon to eat the last one: Kushinada-hime.