The Sith Citadel raid.
In the year 5000 BBY of the Old Republic era, a bold raid was executed by Naga Sadow, who was a Sith Lord. The target of this operation was the Sith Citadel located on the planet Ziost, with the objective of liberating the prisoners Gav and Jori Daragon. Sadow cleverly masked the true nature of the attack, making it appear as if the Galactic Republic was responsible. By doing this, Sadow successfully freed the Daragons, but also killed the respected Sith Lord named Simus during the mission.
