The Anbu (暗部, English TV: Anbu Black Ops, Literally meaning: Dark Side), short for Ansatsu Senjutsu Tokushu Butai (暗殺戦術特殊部隊, Literally meaning: Special Assassination and Tactical Squad), are covert operatives dispatched by their Kage.
Anbu are recruited from their village’s standard shinobi forces, hand-picked by their Kage for their individual capabilities and special skills. Age, background, gender, or previous rank bear no significance in this decision. While on the job, Anbu wear masks and use code names to conceal their identity, leaving only their Kage informed. They typically work in teams, formed on the mission’s requirements. There are apparently no true ranks within the Anbu; team leadership and hierarchy seem to be based on merit and experience. The leaders of the teams are called squad leaders (分隊長, Buntaichō), a position held in high regard.
Anbu protect the village from exceptional threats, conduct high-risk missions into enemy territory, and deal with extremely strong ninja. They are also responsible for carrying out assassinations, tracking, surveillance, and missions requiring specially trained ninja. Some Anbu serve as interrogators that probe the minds of enemy ninja to learn information valuable to the village. Because Anbu are so vital to the village’s operations, they cannot be arrested by regular police forces without a warrant. While many choose to serve in the Anbu for their entire careers, they can return to the standard forces if they choose to, as in the case of Kakashi Hatake