Great Sith Wars

The Great Sith Wars, often known as the Great Sith Civil War, was a conflict that began after Darth Naga Sadow—Salem's apprentice—betrayed her and took her place as Dark Lord of the Sith, though this betrayal only led to infighting among all of the Sith that was part of the original Sith Empire. Each of them breaking off and forming their Sith Empires, claiming to be true successors to the original Sith Empire.

Because she learned how to achieve immortality from the Lamp of Knowledge, she survived the assassination, and before she could bring about order to her fractured Sith Empire, she realized it was too late and entered hiding, founding the Knights of Ren in order to build power to eventually retake control of the fractured Sith. Salem was able to complete her mission 97 years after the conflict began, after she had killed Darth Revan and reformed her original Sith Empire.