The Thirteen Court Guard Squad is the primary military branch of Soul Society. It is also the main military organization that most Shinigami join after the academy. It is a very structured and organized organization, behaving like a military force, mostly because that is what it is. The Gotei 13 serves as a military force with its primary responsibilities consisting of:

• The defense of the Seireitei, the center of Soul Society.
  
• The deployment of Division members into enemy territory for combat operations.
  
• The deployment of Task Forces as defensive measures in the world of the living.
  
• The guiding of souls to the Soul Society.

The Gotei is divided into 13 Squads each with a Captain, a Vice Captain (Lieutenant) and a unique focus.

1st Division-Leadership division. The Captain of Squad 1 is the head of the entire Gotei 13. This squad plans campaigns, recruitment, and other high-level management duties.
Captain:
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th:

2nd Division/Onmitsukido-The Special Forces. Shinigami in Squad 2 are also members of the covert operations team Onmitsukido.
Captain:
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th:

3rd Division-Information and intelligence. Squad 3 members often work with Squad 2 members, as their duties involve gathering information and intelligence. They also manage the Hell's Butterflies. They also deal in counter-intelligence.
Captain:
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th:

4th Division-Medical and supply division. Members of Squad 4 are usually doing one of two things in combat: healing allies or delivering much needed rations and other necessities for long-term battle.
Captain:
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th:

5th Division-Members of the 5th are in general kidou experts, and are often stationed together with 11th Division members, 2nd Division assassins as well as 4th Division healers to form an all-around military group. They are also responsible for all sealing and magical workings inside Soul Society, as well as recording and storing any new kidou.
Captain:
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th:

6th Division-Internal Affairs. The sixth squad monitors Shinigami activity inside Soul Society and is responsible for finding and detaining Shinigami found to be violating Gotei 13 law.
Captain:
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th:

7th Division-Human Resources. While Squad 1 has the final say in policy changes and important events, the members of Squad 7 are usually the ones to deal with more mundane things. This division manages salaries for the Shinigami, deals with conflicts between Shinigami, and reassigns Shinigami if their current Squad isn't a good fit. Many Shinigami interested in psychology work here, because due to the stressful and sometimes traumatizing nature of the Gotei 13's work, this is where Shinigami go for counseling.
Captain:
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th:

8th Division-Reserves and backup. Pretty much explains itself. This squad is large and generally sends members out with small groups of members from other squads to boost numbers.
Captain:
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th:

9th Division-Defensive Tactics and Seireitei Protection. The 9th Division is the ones that actually send out patrols on a daily, frequent basis to survey Seireitei. If a threat occurs, they find and take care of it, sometimes with help from other divisions. They also work together with various divisions.
Captain:
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th:

10th Division-Large-Scale Operations. If an operation involve more than one Squad, there is usually a Squad 10 officer with them to oversee and coordinate the operation.
Captain:
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th:

11th Division-Offensive Tactics. These are the front line troops. Every officer in Squad Eleven loves combat and generally has a melee-type Zanpakutou. The Captian of Squad Eleven traditionally takes on the title Kenpachi. This is generally accepted as the strongest Squad.
Captain: (Kenpachi)
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th:

12th Division/Research and Development Bureau-The 12th Division is in charge of gaining new information through experimentation. They research information that is sent to them from the third division before storing it.
They are also in charge of storing a mass amount of information known to Seireitei in their database. The 12th Division also develops new technology to aid shinigami in their missions.
Captain:
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th:

13th Division-Training and Recreation. This Squad has two duties: it runs all recreational programs within Gotei 13, and the management of the Shinigami Academy.
Captain:
Lieutenant:

SEATED MEMBERS:
3rd:
4th:
5th: