Order of the One Sith (canon)

"'We are one, we are strong, we seek not glory nor a higher sense of self. Instead focus on your hate your anger for your enemies. We are sith.' - a expert from the Stone of pain "The Order of the One sith, also known as the One Sith, is a sith cult founded by a being known only as the Ancient Sith Lord or the Dark lord of the Sith. It was active throughout the Clone wars aiding the Republic and their enemies the Jedi against Darth Sidious and his Rule of Two sith.

The One Sith seek to restore the Sith Empire to its former status, and once and for all destroy the Republic, however unlike the Rule of two the Rule of One allows its members to abide in the shadows growing in strength, number, and power.

Return of the Sith Empire
During the clone wars the Dark Lord of the Sith sent his voice Hemah and a fleet of warships into Republic and Separatist space to deliver his ultimatum, he appealed to planets wanting the war to end and fed up with the Republic's corruption and the Separatist oppression.

Hemah appealed to those worlds to succeed and join the Empire, for doubters he displayed the Empires power by invading and freeing said world from the Republic and separatist garrisons.

Hemah and his fleet arrived outside of a Republic medical station and demanded the Jedi Council met with the Triumvirate. The two sides met on board Hemah's flagship "Redemption" and after 24 hrs of laboring talks the New Sith Empire was recognized by the Republic as a equal not an upstart, and the Jedi Order recognized the One sith as the true sith, and were forced to return worlds and sith artifacts held by the Republic/jedi.