Men In Black, or M.I.B., are an urban legend originating from American conspiracy theories involving UFOs. Dressed in black suits and appearing as government agents, they harass or threaten others to make them keep quiet about any UFOs they see. M.I.B. is also used as a general term to describe mysterious individuals who work for secret organizations.
"An original demon appearing in Ibunroku as Kandori's underling. Dressed in a black suit, it can be seen that its hand and head have been surgically modified. It won't respond to any inquiries from intruders and will attack with the sole intent of killing."