Maggots Nest

The Ujimushi no Su (蛆虫の巣, Nest of Maggots) is a prison under the supervision of the third corps (known as the Detention Unit) of the Onmitsukidō.

It is located on the grounds of the Second Division, and is surrounded by a moat. 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, that Shinigami is brought to the Maggot's Nest for imprisonment, regardless if they were put on trial; this is to ensure no danger will be brought to Soul Society. All prisoners are not held inside a cell (since they cannot set foot outside the prison). Treatment for the prisoners is mostly lenient; they can walk freely and converse with one another, but the bleak setting drives many to madness.

Neither the staff (called jailers) of the Detention Unit 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. If a Shinigami desires to enter and is not adept at hand-to-hand combat, they may not enter. This is to prevent rebellions and escapes from the prison.