Dunbar Fortress is a giant island prison. Hundreds of years ago, it served as a military outpost for the Kingdom of Alterra, however, it was abandoned for political reasons. Since then, it has been reformed and outfitted with holding cells, and is now used by all three kingdoms as a high-security prison. The prison is set up with powerful ritual magic that enslaves its prisoners - cursing them to serve the prison until their demise. This magic means that the prison has no guards, and the Dunbar Jailers are all prisoners themselves, bound by the curse.
Currently, Dunbar Fortress is being watched over by The Shackled King.