Darth Millennial

"It was known by the ancients that a Dark Lord with three eyes has a secret strength possessed by none other."

- Trioculus

Darth Millennial was a three-eyed Sith Lord, heir to the lineage of Darth Bane, who lived at an unknown point in the nearly thousand years separating the Seventh Battle of Ruusan (1,000 BBY) and the Battle of Naboo (32 BBY).

Biography
Nothing is known about Lord Millennial prior to his apprenticeship under Darth Cognus. While still an apprentice, Millennial rejected his master's firm adherence to Lord Bane's restrictive "Rule of Two," which mandated that there could only be two Sith Lords, master and apprentice, at any one time. Instead, Millennial believed in Lord Kaan's more martial philosophy of "Rule by the Strong," and his opposition to Bane's creed indicates he interpreted this to mean the strength of numbers. He abandoned his master, barely escaping with his life, and disappeared to focus on Kaan's ideas, possibly hoping to establish a second Sith order based on these concepts.

Millennial settled on Dromund Kaas, the third planet in a system that had once been part of the backwater regions of the ancient Sith Empire. There he founded a new dark side religion, later called the Dark Force, which was the faith practiced by all his successors. These practitioners, a lineage of mages who called themselves the Prophets of the Dark Side would eventually be rediscovered by Darth Sidious and incorporated into the Galactic Empire he established in 19 BBY. They became the Secret Order of the Emperor, and served as consultants for Sidious during his life and became influential power-brokers after his death.

Behind the scenes
The name may be reminiscent of the word millennium or millennial, which means a span of one thousand years, a hoped-for period of joy, serenity, prosperity, and justice. Relating to a millennium or span of a thousand years, as his master may have been hoping this former Sith apprentice would be, or that the dark side religion he founded wouldn't be found for 1,000 years.