The Anmentai (暗面隊, Dark Mask Unit) is the "sixth" division of the Onmitsukidō. The youngest line in the Soul Society defense, its formation was proposed and organized by the lower noble house of Shumisen following the events of the Winter War. Seeing the aftermath of the betrayal of Sōsuke Aizen and his followers, the Central 46 found it a wise plan of the Shumisen to instill a task force that would survey the internal events within the different military organizations, to prevent another betrayer or, even worse, a coup d'état from arising. Due its nature, the division was formed in absolute secrecy, and there are no official documents of its existence. Besides the members themselves, only the Captain-Commander and the head of the Omnitsukidō are knowledgeable on the actions of the Anmenta