The Purge of the Dark Council occurred in 3950 BBY when Emperor Vitiate of the reconstituted Sith Empire ordered the elimination of the entire Imperial Dark Council, as well as every member of the support staffs of the five traitorous Councilors. While the Emperor's Royal Guard eliminated two of the Dark Councilors, and Jedi Master Revan slew Darth Nyriss, the remaining nine were summoned personally by the Emperor, who then destroyed the unsuspecting Dark Lords.
At the end of the Great Hyperspace War the only survivors of the genocide ordered by the Galactic Republic against the Sith people jumped into uncharted regions in deep space and wandered for twenty years in search of a new home. Over time, the trials and hardships that the Sith had to face during this exile, coupled with the deaths of so many of them at the hands of the Republic and the Jedi, led them to develop a deep desire for revenge, a desire that was fueled by Vitiate.
After twenty years, the Sith fleet eventually found and settled on the jungle world Dromuun Kaas. There, the Emperor promised his people the vengeance that they so strongly desired. He set up plans to rebuild their civilization into a new empire, a society of unrivaled efficiency which would one day rule the Galaxy. He founded the Dark Council, a body of twelve Sith Lords to whom he entrusted the logistical leadership of the Empire. Also, he relied on the non-Force-Sensitive Imperial leaders, such as Odile Vaiken, to prepare his people for the great task that lay ahead. Vaiken drafted every non-Force-user of age into the new Imperial Military and they soon turned into an effective army which started to rebuild a fleet and a gigantic city to serve as their capital. Despite the dedication of the Imperial people, the task of rebuilding was too great to be accomplished in their lifetime and it would be centuries before they would be ready to finally take on the Republic and the Jedi.
As the centuries went by, Vitiate had gradually withdrawn into isolation and essentially left the Dark Council to run the Empire. However, many Sith had grown disillusioned with the Emperor's war plans, believing that the Empire could be destroyed if they fought a too powerful enemy and that all their work would be wasted. They also wanted the power that the Emperor no longer seemed to use and become the true rulers of the Empire. Among these people were several members of the Dark Council, led by Darth Nyriss, who had somehow discovered the truth behind the Emperor's power: how he had sucked all the life on his home world of Nathema and blamed it on the Jedi, how he had known where Dromund Kaas was since before the Sith's exile and how he had lied to the Sith in order to turn them against the Republic and the Jedi. Nyriss and her allies planned to put an end to the Emperor's madness before he led them all to war. She gathered as much support as she could for her upcoming coup.
When she wanted to recruit the Sith Lord Scourge, she took him to Nathema and told him the story of the Emperor and his deception to the Imperial people. Scourge, who also came to see the Emperor's evil nature, agreed with Nyriss that he had to be killed. It was while they were on Nathema that Nyriss and Scourge captured the Jedi Knight Revan who had once discovered the existence of the Sith Empire and had now come to end its menace. They held Revan for three years as a prisoner and for information about the Republic. Ultimately, Nyriss gave up on her prisoner and focused her attention on her rivals. Scourge, in turn, slowly became dissatisfied with the conspiracy's unwillingness to act against the Emperor. During the intervening three years, Scourge slowly built a rapport with the captive Revan and understood that no member of the conspiracy would dare take charge without being betrayed. Later, one of Revan's former students, Meetra Surik, came looking for him and she allied with Scourge to free Revan and kill the Emperor.
Scourge demanded an audience with the Sith Emperor, something incredibly risky since the only ones allowed to see the Emperor without being invited were the members of the Dark Council. The Emperor however, pleased by Scourge's boldness, granted the audience. He accepted the Sith Lord's information on the conspiracy within the Council, which he stole from Nyriss' assistant Sechel, as the truth and announced that he would take action.
The Imperial Guard, led by Captain Yarri, attacked Nyriss and two other co-conspirators less likely to answer the Emperor's summons. Nyriss herself was killed by Revan who had escaped with Surik's help. The Dark Lords' support staffs were also killed in the purge. The rest were summoned to the Emperor's Citadel and did not walk out alive. The Emperor had seen that the Council's support of the war had wavered and he could no longer count on them for support of their plans. This was his opportunity to not only get rid of them and impose new, pro-war members but also remind the Imperial people who really ruled them.
After the massacre of the Council (back then the public faces of the Empire), confusion swept over the people and this led to unprecedented unrest amongst the Emperor's subjects. Riots erupted across Kaas City, leading the Emperor to take immediate action. He imposed martial law and a curfew over the planet while at the same time initiating a lockdown which prevented any ship from landing or leaving Dromund Kaas. It was during this time that Scourge (with the help of Revan and Surik) had also planted disinformation around the population as a part of the plan to kill the Emperor, hoping to use the unrest as a distraction; while Imperial troops were busy dealing with the riots, the three of them would slip into the Imperial Citadel and finally put an end to the dark side monarch.
The riots were eventually controlled by Imperial troops as the population was still fiercely loyal to their Emperor by the time of the Great Galactic War. As it was, the newly installed Dark Council all fully complied with Vitiate's plans for war with the Republic. Later on however, Revan's attempt to kill the Emperor would up in failure. Scourge, who had seen in a Force vision that the Emperor would be killed by a Jedi but not by Revan and Surik, killed the latter and this allowed the Emperor to capture Revan. The Jedi Knight was placed into a stasis in which the Emperor tried to pry information about the Republic from his mind. However, aided by Surik's spirit, Revan was able to resist the Emperor's power and planted seeds of doubt in his mind about his invasion of the Republic so as to delay it as long as possible. He managed to hold off the Emperor from his plans for more than 300 years but his final fate remained unknown until he was freed by a Republic strike force under the guidance of Surik's spirit.
Scourge, as a reward for his supposed betrayal of Revan and Surik, was made into the first Emperor's Wrath, the Dark Lord's personal enforcer, and he was granted the same immortality that Vitiate himself possessed (at the cost of his own emotions). Scourge was planning on waiting until the Jedi and the allies from his vision revealed themselves to defeat his dark master, at which point he would join them.
- The Old Republic: Revan (First appearance, simultaneous with The Old Republic: Revan audiobook)
- The Old Republic: Revan audiobook
- Star Wars: The Old Republic (Codex entry) (First identified as Purge of the Dark Council)
- Star Wars: The Ultimate Visual Guide: Updated and Expanded
- The Essential Reader's Companion
- Star Wars: The Old Republic Encyclopedia