Das Stärkste Gefängnis ( Dasu Shutarukusute Gefengunisu; Ger: "The Strongest Prison") is a class of Demon related to the King of Time, Mephisto Pheles.
A demon summoned by Mephisto in order to contain Rin Okumura, it is a stationary metal box with entrances on both sides. The door can open for a large metal claw to grab the target of the Gefängnis.
Powers and Abilities
Time Stop: Das Stärkste Gefängnis can freeze time for those who approach it with ill intent.
Pocket Dimension: The interior of Das Stärkste Gefängnis contains a field of broken gears and debris that is larger than its outer dimensions.