Onmitsukidô

Commander in Chief: Captain Squad 2
Executive Militia Leader: 3rd Seat Squad 2
Patrol Corps Leader: 4th Seat Squad 2
Detention Unit Leader: 5th Seat Squad 2

Also called the Secret Mobile Unit/Corps, Special Forces or Covert Ops, is one of the three branches of the military under the control of the Central 46 Chambers, the others being the Gotei 13 and the Kidô Corps.

Special Forces Division:

Executive Militia: The first branch of the Onmitsukidô. It is ranked the highest of the five branches in the division. Their responsibilities including punishment and assassination of ex-comrades who break the law and acting as scouts during battle against Hollows.[3] Its members are dressed all in black and are known for their cold-bloodedness. They specialize in combat using Hakuda. It is normally headed by the the Commander-in-chief of the Onmitsukidô.

Patrol Corps: Their apparent job is to patrol the Seireitei. In the event of those under house arrest escaping they also are tasked with finding and apprehending them. Externally they patrol the various lands and dimensions to combat dangerous Hollows and other enemies of Soul Society.

Detention Unit: The Detention Unit is responsible for the imprisonment and supervision of all criminals within the Seireitei. They also have another duty known as Special Detention, which concerns those who joined the Gotei 13 but were judged to be a danger to their fellow Shinigami. They investigate, apprehend, and keep these individuals sealed away from the rest of Soul Society within the Special Underground Detention Facility, aka. the Nest of Maggots. It should be noted that those few who are kept in the Maggots' Nest have not actually committed any crime but have been identified by the laws of Soul Society as "Dangerous Elements". This unit acts somewhat similar to a prison and mental rehabilitation center.