"Imprisoned behind these walls, gang leaders are fighting a bloody war in the middle of our once great city. Every inmate from Arkham Asylum and Blackgate Prison has been relocated to this facility. How can this be safe for the people of Megaville"
-Young Autobot to the press conference about Arkham City.
Arkham City is a massive super-prison that is the new incarnation of "Arkham Asylum" and it was created in the middle of Megaville & Elmore by Professor Hugo Strange & Dr.X. Underneath Arkham City is a Dwarven city where Vulthuryol resides.