Star Wars: Imperial Entanglements
Designated TC-534, the Impregnable is an Imperial black-prison ship. It is not detailed on any official records, but transports sensitive and high-risk prisoners on a circuitous route around Hutt space.
It’s route takes it from the Outer Rim (especially the Kessel, Bheriz, Baxel Albanin, Al’Nasrl and Galov sectors) around Hutt space and into the Mid Rim to an Imperial prison on Nanth’ri in the Kurost Sector.
It is commanded by Captain Golrin Pollak.