General BG Info
The ANBU (暗部, ANBU; Viz "Black Ops", English TV "ANBU Black Ops"; Literally meaning "Dark Side") is actually short for ANsatsu Senjutsu Tokushu BUtai (暗殺戦術特殊部隊, Ansatsu Senjutsu Tokushu Butai; Literally meaning "Special Assassination and Tactical Squad"). The name is a form of contraction, similar to English acronyms like SWAT, where the two kanji used to abbreviate the group's full name constitute an actual word on their own.

Purpose
ANBU are under direct control of their Kage. They protect the village from exceptional threats, conduct high-risk missions into enemy countries, and deal with extremely strong ninja. They are also responsible for carrying out assassinations 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. If an ANBU dies dug a mission they are required to destroy their bodies.

Uniform
The ANBU wear porcelain animal masks in order to distinguish themselves from normal shinobi and to conceal their identities. They also have standard uniforms consisting of black and gray armor, arm guards, and a signature spiral tattoo on their left shoulder (female ANBU members have the tattoo located on their right shoulder to determine gender between the ANBU members). Some ANBU wear black cloaks over their standard uniforms, and squad leaders may wear white cloaks.

Members of the Anbu
Anbu Captain :: Robin Kankaku aka Same
Anbu Members ::
Ayumu Peinto aka Kuro [Second in command]
Seth Kamen aka Kamen
Jiro aka Rookie/Arata

Anbu Black Ops will take place when Syn and Jiro complete their Anbu Update Applications.

The following thread is out of date, inaccurate and due to be overhauled shortly