Eternal Empire conquest Around 3637 BBY , the emerging Eternal Empire launched a campaign of conquest into the Core Worlds , defeating both the Galactic Republic and the Sith Empire , the known galaxy ' s major powers . Prelude . During most of the Sith Emperor ' s absence from reigning his Sith Empire , he had been secretly developing a new empire , the Eternal Empire , positioned in uncharted territory within Wild Space and with its capital on the planet Zakuul . There , known as Emperor Valkorion , he built and strengthened his forces to one day emerge and conquer the galaxy . By 3637 BBY , the Sith Empire ' s few outposts in the Wild regions had been wiped out by the Eternal Empire to test the latter ' s strength although the Sith Empire was unable to discover the culprits . Soon that year , as the Galactic War raged between the Sith Empire , Republic and third parties , the Eternal Empire launched raids and decimated several of their planets , including Korriban , before retreating back into Wild Space . Darth Marr , " de facto " head of the Dark Council and the Imperial Military , led a joint Imperial - Republic expedition into Wild Space to pursue the Emperor , only to be ambushed by the Eternal Fleet . Marr and another prominent figure , who would become known as " the Outlander " , were captured from Marr ' s destroyed flagship by Prince Arcann , the surviving son of Valkorion , and brought to the Emperor on Zakuul . Valkorion offered to share his power with his captives if they would kneel before him . Marr , recognizing Valkorion as the Sith Emperor , refused , and was killed for his defiance . As he offered the same to the Outlander , Valkorion was killed , and Arcann assumed the throne in his place . The new Emperor publicly accused the Outlander of his father ' s assassination , and declared that the Core Worlds would burn as a result . The Outlander was frozen in carbonite , as Arcann sensed that Valkorion lived on within the mind of his " murderer " . The war . Arcann ' s war was swift and brutal . Directing the fleet from the Eternal Throne , the new Emperor attacked both Republic and Empire at once , destroying their shipyards and blockading the major trade routes . The Eternal Empire had numbers and speed on its side ; only ships powered with isotope - 5 could hope to evade the more powerful vessels of the Eternal Fleet . Within three months , they had achieved naval superiority over both sides , and by the end of the first year , the Republic capital of Coruscant and the Imperial capital of Dromund Kaas were blockaded . The Dark Council of the Sith Empire fought on , but without Marr ' s leadership , the Council was all but destroyed . Similarly , the Republic ' s Supreme Chancellor , Leontyne Saresh , refused to submit the Republic to Zakuulan authority - and , incredibly , waged a war against both the Eternal Empire " and " the Sith Empire , at the cost of millions of Republic lives . Saresh was swiftly overridden by the Galactic Senate , which sued for peace . The Minister of Logistics did likewise for the Empire . Both sides sent emissaries - Senator Evran for the Republic , and Darth Vowrawn for the Empire - to Zakuul , where they were brought before Arcann . The Emperor agreed to a ceasefire , provided that the Republic and the Empire pay heavy tribute to Zakuul and submit to armament restrictions . With little option left to them , both sides agreed . In the years that followed , Saresh was out of power , but continued to dictate policy through her successor , Jebevel Madon . Similarly , with the Dark Council practically dissolved , its one visible remaining member , Darth Acina , declared herself Empress of the Sith . Even after this , the war between the Republic and the Empire continued - Saresh unwilling to even consider any form of alliance with the Sith to overthrow the Eternal Empire - and Arcann allowed it to continue , provided that they acknowledge the supremacy of Zakuul , and continue to pay the tribute demanded of them . Rather than control his new holdings with occupation armies , Arcann deployed hundreds of massive battle stations known as Star Fortress es in orbit around major planets , such as Alderaan , Belsavis , and Voss . These battle stations were commanded by Exarchs - Knights of Zakuul enhanced by biological and cybernetic upgrades - and were empowered by great " sun generators " , essentially artificial stars ( similar to those used on Zakuul itself ) , and protected by shield generators built on the surface . Any attempts at resistance were answered by the stations venting excess plasma from the sun generators into devastating beams fired at the surface , essentially holding the planets and their populations hostage .