The conflict known as the Duel on Bosthirda effectively eliminated the threat posed by the Bosthirda separatists to the Reformed Sith Empire. This was achieved when the loyal Sith Lord Scourge vanquished Darth Xedrix, a Dark Councilor who was secretly in league with the separatists.
Around the year 3954 BBY, Darth Nyriss, along with Darth Xedrix and several other members of the Dark Council, were actively conspiring to overthrow the Emperor. They believed him to be arrogant, excessively powerful, and insane, and they considered his strategy of attacking the Republic to be a suicidal endeavor. To maintain the secrecy of their alliance from the Emperor, Darth Nyriss orchestrated fake attempts on her own life. Initially, the plan was for Nyriss's own followers to investigate these attempts, but the Emperor intervened by dispatching Lord Scourge, leading to a change in their strategy. Sechel, another of Nyriss's subordinates, and Scourge successfully uncovered that a group of Human separatists originating from Bosthirda were responsible for the assassination attempts. During a raid on their compound, they discovered evidence indicating Xedrix's collaboration with the separatists.
Scourge, utilizing a replica of the separatists' encrypted communication methods, sent a message to Xedrix while impersonating the separatists. In this message, he requested Xedrix to meet them at a cave located on Bosthirda. Xedrix journeyed to the designated location, accompanied by one male Human apprentice and one female Human apprentice. Upon their arrival, Scourge launched an attack, defeating and killing both apprentices. Xedrix, weakened by age and the extensive use of the dark side, mustered his strength for a final assault and unleashed Force lightning upon Scourge. Although injured, Scourge recovered and prepared to eliminate the Sith Lord. Xedrix attempted to sway Scourge to his cause by falsely claiming that Nyriss had sent him to his death and, truthfully, revealing that she was manipulating him as a pawn in a larger scheme. Scourge remained unconvinced and, recognizing the Sith's frailty as Nyriss had described, he killed Xedrix and presented his severed head to Nyriss as proof of the Sith's demise.
With this it seemed that Xedrix was the one behind the assassination attempts, and the situation remained the same, with Dark Councilors plotting and the Emperor watching; but everything changed later with the arrival of Revan in the Empire's territory with most of his memories restored.