The dimensional prison (次元牢 jigen rō) is a special prison that does not exist in this world. It was said that no human being can escape this place.
In BlazBlue: Chronophantasma, Kokonoe Mercury and Kagura Mutsuki started the Battle of Ragna the Bloodedge to lure out Azrael and capture him into the dimensional prison. Ragna the Bloodedge, and then Kagura himself, distracted Azrael while Kokonoe was tuning the teleport. After Kagura figured out that Azrael cannot fight those who do not want to fight him, Kokonoe teleported the Mad Dog to TR-0009 Tager, and after the latter punched him, she teleported Azrael into the dimensional prison.
In BlazBlue: Centralfiction, Azrael escaped from the prison by tearing it apart with his bare hands.