Kurenai had to think about it for a moment, the Empire did no so much as end but more splinter up, individual Moffs taking control over their sector of space, then something with a man called grand admiral Thrawn. "You could say that the Empire was defeated at the battle of Jakku where the Reble alliance and the last of the Imperial fleet went toe to toe, after that things are a bit, odd to say, many wars with alien species like the Vong that plagued the new republic or alliance as some called it".
As for the Sith Empire, well that was a bit more complicated, "The Sith empire of today are remnant of the One Sith, that order being a reestablishment of the One Sith over 600 years ago, the new One Sith empire but 20 years ago bringing the Republic to its knees". "In it's wake the Galactic Alliance was formed, driving to the One Sith home world and defeating them, but leaving much destruction in its wake". "From that the Silver Jedi where formed a more militarist Jedi that wanted to prevent a faction like the one Sith from rising, the Ren getting old stories after the attack on Coruscant going ahead and making the First Order, the imperial remnant with the fall of the Republic looking to make a com back".
She took a small sip of tea letting the other soak in the information, "In addition there were some smaller factions, the Dominion, a coalition of Sith and Jedi who had been left with nothing after the war establishing themselves on Sereno, The Resurgant Empire, made of Sith who still wanted to fight, making a base on Korriban, the two often fighting". "But the Sith Empire of today, that was officially called the Sith ascendancy, a Sith Order dedicated to keeping peace and order, a more... peaceful order, gaining ground with not much opposition, until they joined forces with the Sith Brother hood". "The brother hood where those Sith plagued by the though of killing every last Jedi, soon waging war on the Dominion, and absorbing the Resurgent Empire into its borders, decimating the Silver Jedi".
"But not all Sith were happy with the new Empire, a Man called Darth Metus soon formed a new Confederacy of Independent system around Genonsis, allying with the Alliance and Silver Jedi, waging war upon the Galatic Empire". "In addition a faction called the outback or Outer Rim Coallition fights with the Alliance against the First Order, as well as the monarchy of Alderan against the Sith with the Commoner System Alliance staying neutral". It was a lot to take in, herself still not explaining the Commonwealth Iron empire, metal lords or the two new faction, the Sovereignty and Ancient Eye.
(FYI I go by Legends and old time line canon since the site was made in before the new star wars movies so the whole One Sith Empire and book series is what most people consider cannon on here [member="Invicta Jos"] [member="Rex Taff"])