The central penal facility used by the monarchy was situated in Sundari, the capital city of the New Mandalorians on the planet of Mandalore. This entire complex was suspended in the air, high above the urban landscape.
During the era of the Clone Wars, Duchess Satine Kryze found herself wrongly accused and incarcerated within this prison. This was orchestrated by Prime Minister Almec, who sought to coerce her into signing a false declaration. The statement would have implicated her in the Mandalorian black market conspiracy, effectively concealing the Prime Minister's own culpability. However, the scheme was foiled by the opportune intervention of Jedi Ahsoka Tano alongside four students hailing from the Royal Academy of Government: Amis, Lagos, Soniee, and Satine's very own nephew, Korkie Kryze. Together, they successfully liberated the Duchess. Following a swift skirmish, Almec and his guards were apprehended, leading to Almec's own imprisonment for his offenses against the Duchess and his involvement in the aforementioned conspiracy.
Later, when Darth Maul and Savage Opress seized control of Mandalore, Pre Vizsla took Duchess Satine Kryze into custody. She was then confined within her own prison, specifically in a cell adjacent to that of the former Prime Minister, Almec. Not long after, Vizsla turned on Maul and Opress, imprisoning them in a bid to claim sole dominion over Mandalore. However, Maul and Opress managed to break free, and after a conversation with Almec, freed him so he could be a puppet leader for them. The trio then left the prison and and Maul killed Vizsla as payback for his earlier betrayal.
Following Maul's assumption of power, Satine experienced two separate rescues from the prison. The initial rescue involved Korkie and Bo-Katan Kryze infiltrating the prison and successfully freeing Satine, while eliminating at least two Mandalorian super commandos in the process. They successfully escaped with assistance from Korkie's friends and Bo-Katan's loyalists within the Death Watch. They managed to extract the Duchess from the city, enabling her to transmit a distress signal to Obi-Wan Kenobi. Despite this, she was eventually recaptured and re-imprisoned. Subsequently, Kenobi journeyed to Sundari and facilitated a second escape for the Duchess. He concealed his identity by donning armor acquired from a super commando, escorting Satine out of the prison under the pretense of a prisoner transfer. Regrettably, their attempt to leave the planet was thwarted, and this time, Maul tragically murdered the Duchess right before Kenobi's eyes. Kenobi was to be imprisoned, but upon his arrival at the prison, he was liberated by Bo-Katan and her forces, igniting the Battle of Sundari.