Slaughter of the Ascendant

Centuries before 4 ABY during the era of the Sith, the Sith slaughtered the entirety of the Ascendant, a cult that used technology to utilize and replicate the powers of the dark side. The attack took place in the Unyielding Heart, a chamber of the Tomb of the Spark Eternal on the planet Bar'leth that housed the Spark Eternal, a sentient piece of technology created by the Ascendant that granted the user enormous power for the price of their life. The Sith sought the Spark Eternal, but an Ascendant cultist named Miril used the Spark to telekinetically stab many of the Sith with their own lightsabers. However Miril was still overcome by them, and gave her life to seal the Spark Eternal away and prevent the Sith from retrieving it. With Miril dead, the rest of the Ascendant crumbled and were all killed by the Sith.

Sometime between 3 ABY and 4 ABY, archaeologist Doctor Chelli Lona Aphra discovered the Spark Eternal and was possessed by it, which allowed her to reach into the Spark's memories to see and learn about the slaughter and defeat of the Ascendant.

Text and facts from the “Slaughter of the Ascendant” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.