This article contains spoilers for Star Wars #20.
New Star Wars comics just rewrote the history of the Sith, Darth Bane, and the Republic. Unarguably one of the greatest Sith Lords, Darth Bane was the one who recreated the Sith, establishing the Rule of Two. As George Lucas explained in an interview with TIME Magazine, the ancient Sith embraced the dark side - and turned on one another, each burning with a self-centered lust for power. "Eventually, there was only one left," Lucas explained, "and that one took on an apprentice. And for thousands of years, the master would teach the apprentice, the master would die, the apprentice would then teach another apprentice, become the master, and so on." The Rule of Two ensured the conflict between the Sith never escalated to the point of risking their extinction.
The novelization of Star Wars: Episode I - The Phantom Menace named the founder of the Rule of Two as Darth Bane, with Lucas himself confirming this in episodes of Star Wars: The Clone Wars. The old Expanded Universe explored his story in a popular trilogy by Drew Karpyshyn, but this story was rendered non-canon when Disney acquired Lucasfilm back in 2012, with the EU branded "Legends." The Disney canon has redefined the Rule of Two, revealing it was bound to the Sith Doctrine of the Force Dyad, an attempt to unlock a power beyond life itself. But Darth Bane's story has yet to be told.
Star Wars #20, by Charles Soule and Marco Castiello, finally reveals a little about the canon backstory of Darth Bane - and it's very different from Legends. The issue sees Luke visit a world rich in the Force, where he has a mystical encounter with a Jedi from the High Republic Era - some 200 years before the main Star Wars saga - named Elzar Mann. During the conversation, Elzar recalls his own time. "This is what the Order was for me," he reflects as he casts a vision into Luke's mind. "A golden age, about eight centuries after we ended the rule of Sith Lord Darth Bane." It's only a throwaway comment, but it recasts the history of the Sith and Darth Bane, revealing a thousand years ago he ruled an Empire that the Jedi overthrew.
In the first Star Wars movie, Obi-Wan Kenobi claimed the Jedi had served as guardians of the Republic for a thousand generations. But, just as in Legends, there seems to have been times when the Republic shrunk, when it was threatened by rival Sith Empires. Darth Bane's Empire was presumably one of its challengers, and his defeat led to the birth of the Republic. After all, in Star Wars: Episode II - Attack of the Clones, then-Chancellor Palpatine insisted he would not "let this Republic, that has stood for over a thousand years, be split in two."
It's interesting to note that Luke Skywalker knows nothing of this. When he became Emperor, Palpatine worked hard to obscure the galaxy's history, attempting to destroy all trace of the Jedi's existence - and hoarding knowledge of the Sith because he did not want any challenges to his power. Luke was educated in the Dark Times of the Empire's reign, and his knowledge of Sith and Jedi history was incomplete at best. From an in-universe perspective, that's why so little is known about the galaxy's history - meaning remarks like those from Elzar Mann are crucial, helping fans get to grips with the past of the Star Wars galaxy.