Blackgate

"The hell in Remnant" that was the best word to describe it and it was first mentioned by Ian Belladonna when he was going to be arrested.

History
At some point during the medieval times, Ozma used his influence to create an experimental prison. This was mainly to transform criminals, as a high security prison, the most powerful or intelligent people ended here, alongside the technological advance, the methdos to transform criminals got better, however, when the General James Ironwood took over decided to take down all of the transformation programs and instead turn it into the hell in Remnant to get information out of the criminals and also for executions, luckily for criminals the General Winter Schnee took the programs back.

Fall of Blackgate
At some point, Ian Belladonna and Exter Ironwood got arrested, and of courses the other two Beacons had to rescue them. Duncan threw a full scale attack at the Blackgate, commanding the Dark Redeption, Fallen Fang, Reborn, Covenant and Hot Road. It left the Blackgate almost completely destroyed and setting all of the criminals free, including Scissors Dan, the first prisoner there.

Description
A maximum security prison to transform criminals into better people willing to work with the justice.