Before the events of 4 ABY, specifically during the era of the Sith, the Sith engaged in the wholesale slaughter of the Ascendant. This cult, known for its technological exploitation and duplication of dark side abilities, was completely eradicated. The Unyielding Heart, a specific room within the Tomb of the Spark Eternal located on the planet Bar'leth, served as the location for this massacre. The Spark Eternal, a self-aware technological artifact created by the Ascendant, resided within this tomb. It bestowed immense power, but at the cost of the user's life. The Sith's objective was to seize the Spark Eternal. However, an Ascendant cultist named Miril bravely used the Spark to telekinetically turn the Sith's lightsabers against them, striking down many. Despite her efforts, Miril was ultimately defeated. She gave [her](/article/gender] life to seal the Spark Eternal, preventing its acquisition by the Sith. With Miril's death, the Ascendant were utterly defeated, and the Sith killed them all.
At some point between 3 ABY and 4 ABY, the archaeologist Doctor Chelli Lona Aphra unearthed the Spark Eternal. This discovery led to her possession by the artifact, granting her access to the Spark's memories. Through these memories, she witnessed and learned about the Ascendant's slaughter and ultimate demise.