Frozen Prison

Frozen Prison is the maximum-security prison where the Great Tomb of Nazarick keeps its captives.

Layout & Features
The Frozen Prison resembles a fairy-tale castle, but within is anything but magical. Various wraiths and undead lie in wait, hidden from seeing eyes to launch themselves at trespassers. Based in the fifth floor of Nazarick where the entire terrain is a frozen wasteland, escape from this stronghold is impossible.
 * Room of Nigredo: The cell where Nigredo, Overseer Guardian Albedo's sister, is kept in confinement. The entrance to her chamber is disguised as a painting of a mother cuddling her baby.
 * Room of Truth: Neuronist Painkill's personal place of office. In other words where Neuronist and her Torturers process freshly caught captives for interrogation.  Its filled with a number of horrendous torture contraptions and equipment.

Trivia

 * It is said that the temperature inside the prison is even lower than that of the Arctic world of the fifth floor.