Nest of Maggots

The Nest of Maggots is a place in Seireitei which serves as a prison under the supervision of the third corps of the Onmitsukidō, also known as the Detention Unit. On the inside, it resembles a cave with an area for prisoners.

When a Shinigami becomes a potential danger to other Shinigami and Soul Society itself, then that Shinigami is brought to the Maggot's Nest for imprisonment, even if that Shinigami was not put on trial; this is to ensure that no danger will be brought to Soul Society. Most prisoners are not held inside a cell (since they cannot set foot outside the prison), with the exception the Maggot's Nest's most infamous former resident: Mayuri Kurotsuchi, considered at the time an exceptionally dangerous person. treatment for the prisoners is mostly lenient; they can walk freely and converse with one another, but the bleak setting drives many close to madness.

Neither the staff of the Detention Unit, who are called jailers, nor any other visitors are permitted to carry a Zanpakutō into the Maggot's Nest; visitors must deposit them at the entrance. This measure means that the jailers are required to be able to control the prisoners with bare hands, so if the Shinigami entering isn't an adept at hand-to-hand combat, they may not enter. This is to prevent rebellions and escapes from the prison

Kisuke Urahara, as Corps Commander of the Detention Unit, was once in charge of the Maggot's Nest before being promoted to Captain of the 12th Division. During the visit, he demonstrated to Hiyori Sarugaki that he is capable of subduing even the most physically powerful prisoner in the Maggot's Nest with his bare hands, which he described as a key requirement of the Detention Unit Commander's position.