Devil's Gulag

Devil's Gulag, more properly known as the Devil's Island Gulag, was once the primary prison used by the Kingdom of Acorn to hold its most dangerous captives. A fortress situated atop a tall spire in the middle of a ring of active volcanoes, the gulag is surrounded by boiling ocean waters at a temperature of 220 degrees Farenheit, hence it's name. These features, combined with the security of the fortress itself, made escape seem an impossibility. However, due to the intervention of Dr. Eggman and his orbiting satellites, all of Devil's Gulag's inmates escaped during Sonic the Hedgehog's search for Ixis Naugus. A number of them would later be returned there, only to escape again; following the reclamation of Mobotropolis and its return to being Robotropolis due to Eggman's machinations, prisoners were kept in an unsophisticated prison in Knothole. Following the destruction of that city, a new high security penitentiary was designed and created by NICOLE, thus rendering Devil's Gulag redundant and effectively abandoned.

Prison for Convicts
Established at an unknown point before Dr. Ivo Robotnik took control of the Kindgom of Acorn, Devil's Gulag was brought into service again shortly before his death. Following his betrayal of the Robotropolis Spy Network, Sleuth Dawg was sentenced to be imprisoned there, but was not transported until after Sonic was accused of the seeming murder of Sally Acorn and likewise sentenced there. Their transport would be shot down by SWATbots before they could arrive, but while Sonic escaped, Sleuth was recaptured and taken to the Gulag. He would later be joined there by a number of other criminals: Nack the Weasel, Drago Wolf, the members of the Fearsome Foursome-Sergeant Simian, Predator Hawk, Lightning Lynx, and Flying Frog-and Snively Kintobor. The last inmates to be brought to the Gulag would be the crystallized Warlord Kodos and Uma Arachnis. (StH: #42, #47, #48, #50, #54)

Breakout
Snively wracked his brain over escaping from the Gulag, with his fellow inmates mocking him at every turn. However, their last taunt session coincided with the moment that a satellite activated in orbit by Dr. Eggman unlocked all the doors in the prison. The inmates were freed, and with the exception of Snively all thought him to be responsible for their liberation. Led by Drago, the criminals quickly overpowered the guards and laid waste to the fortress, escaping aboard a number of hovercraft. After some time working together as a group, the escapees were splintered by the Royal Secret Service in their rescue of Nate Morgan, resulting in the capture of Drago, Sleuth, and the Foursome, who would later escape the Gulag again and reorganize as the Destructix. (StH: #62, #63, #70, #162)