The Citadel

The Citadel was a supermax prison located on the volcanic planet Lola Sayu. It was built by the Republic for holding Dark Jedi and other Force-using criminals, and administered by Jedi Shadows before its loss to the Confederacy of Independent Systems.

Republic
In the Galactic Republic, the Citadel was used to hold Dark Jedi and other Force-using criminals. It was built circa 520 BBY. The Citadel's commandant, deputy commandant and several other officers were Jedi Shadows. Service in the Citadel was associated with exposure to the basest desires of the Dark Jedi imprisoned within, boredom and heavy alcoholism among guards and general wanton cruelty, so it was considered the least desirable kind of service among the Shadows. The offices of the Citadel were never filled voluntarily; it was the place where the careers of less than capable Shadows were reassigned to die. As Maw once put it, the wardens of the Citadel were its prisoners, too, just one ster higher in the food chain than the inmates.

In 22 BBY, Rina Ascura and Maw were holding the positions of commandant and deputy commandant of the Citadel respectively.