The Onmitsukidou

The Onmitsukidou, or the Secret Tactics, are the Seireitei’s last line of defense. While the Kidoushuu manages and operates the spells and libraries and the Goteijuusantai cleanse the world of hollows, the Onmitsukidou moderate both factions, and in truth, everything dealing with shinigami. They find criminals, assassinate them, relay messages between divisions, and imprison potential threats to the health of the Seireitei. 

Before the reign of Nibantai-Taichou Yuu Yashin, they were joined to the Goteijuusantai in order to consolidate power; however, with him not being apart of their fold, they have slowly began to break away from their shinigami brothers. 

Much like the Kidoushuu or Goteijuusantai, the Onmitsukidou is organized into five unique forces. Each force is lead by a shinigami elected by that force and that force alone, and then approved by the other commanders. These commanders meet often to share information and to plan ahead for their organization. These commanders are called the Gundanchou (軍団長 lit. corps commanders). They were formally lead by the Sōshireikan, ((総司令官 lit commander-in-chief), though one has not existed for hundreds of years. 

The forces are as follows: 

KEIGUN| The Keigun are the punishment force of the Onmitsukidou. They each wear a unique uniform of all black, and appear much like the typical fantasy ninja. The Keigun is the most elite unit and the hardest to become a part of, requiring a six additional years to fully join. Upon doing so, their names are often replaced. Their duties include the assassination of rogue shinigami and acting as scouts when searching for hollow.  

KEIRATAI| The keiratai are the spies within the Onmitsukidou. These individuals actively perform espionage in all branches of the military within the Seireitei, and are constantly gathering information. More specifically, they gather data on things such as uprisings and rebellions. There is no defined uniform for these shinigami beyond that of the traditional shinigami garb. 

KANRITAI| The Kanritai are the gaolers and wardens of all prisons and dungeons within the Seireitei. They manage every single prison, including Central. More specifically, they control the top secret prison known as the Maggots Den. The knowledge of the Maggots Den is unknown beyond the Central 46, Soutaichou, and Onmituskidou. They are the most secretive branch, and the only way to join this force is to be transferred from another. 

RITEITAI| The Riteitai are the special ops members that transfer missions and perform secret missions that require speed and finesse for the Onmitsukidou. Their uniforms wear bamboo hats that cover their face and hair and are triangular in shape. Additionally, they wear form-fitting pants, a red outer kosode, and a purple backpack containing various supplies. The members of the Riteitai are the fastest within the Onmitsukidou, and many are masters of shunpo. 

UNEITAI| The Uneitai are the core of the Onmitsukidou. They are the veterans, who train, educate, create the uniforms, forge the weapons, and manage the operations of the entire stealth force. Much like the detention unit, they are promoted from within, and only the oldest, most seasoned, and most well known members are added. Their uniform is the traditional shinigami garb.