First Division (Fanon Canon)

The First Division (一番隊, Ichiban-tai) is the first of the Gotei 13 Divisions. It is considered to be the leader division among all thirteen, as its Captain is the Commander of the Gotei 13 in its entirety.

Special Duties
The First Division is ranked highest among the 13 Divisions. Even subordinate members of the First Division are considered model Shinigami. Emergency must be dealt with swiftly; quick decisions and quick actions are essential. The division is able to ascertain a situation and mobilize quickly even before an order is issued. That is the true value of the First Division.

However, they are also tasked with the main duty of serving as the wardens for the Central Great Underground Prison.

Barracks
Like all the other barracks, the 1st Division Barracks house the offices and living quarters of the Shinigami of the 1st Division. In addition, due to the 1st Division being the division of the Captain-Commander, the barracks hosts the assembly hall where the captains gather for their meeting. The barracks also has a room set aside for lieutenants' meeting. Captain-Commander Shunsui's office within the barracks commands a wide, sweeping view of Seireitei.

Directly underneath the division's barracks lies the Central Great Underground Prison.

After Yamamoto's death, the shattered and scorched Ryūjin Jakka was returned to the barracks.