The Halbert is a legendary faerie weapon.
the Halbert was given to a half man half faerie by his mother to use in battle. She told her son to use it for good or he'll go insane. The warrior kept his mother's word and defeated those who threaten the village, becoming a hero. But he discovered that his lover was with another man and he killed them both. From there he became insane, killing everyone.
Episode 9 Edit
Prior to episode 9, a business man obtained and carried the legendary weapon. It then came into the possession of Naoki Miki.