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 Special Forces, 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 proven guilty in any way. This was to ensure that no danger will be brought to Soul Society. Most prisoners ar not held inside a cell (since they cannot set foot outside the prison either way) with the exception of Mayuri Kurotsuchi (about a century ago) which implies that he is of high-level danger.

Neither the staff of the Detention Unit, who are called jailers, neither any other visitors are permitted to carry a Zanpakutō into the Maggot's Nest, they have to deposit it at the entrance. This measurement also means that the jailers are required to be able to master the prisoners with bare hands.

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. It is seen that he could take care of any prisoner with his bare hands by Hiyori Sarugaki.