In 18 BBY, the Illumine Kilhorde, which constituted the battle fleet belonging to the Kilji Illumine nation, undertook conquests of enlightenment in areas close to the Unknown Regions of the Chiss Ascendancy nation. The purpose of these conquests was to disseminate the Illumine's religion. Under the direction of the Grysk operative "Jixtus," who had formed an alliance with the Illumine's leader, Generalirius Nakirre, the Kilhorde subjugated multiple nations, planets, and populations.
However, Thrawn, a Senior Captain within the Chiss military, had retrieved intelligence regarding the Kilhorde's vulnerabilities from the Kilji picket cruiser Hammer and subsequently shared it with the Paataatus Hiveborn nation. The Hiveborn considered the Kilji conquests, which were progressing to the south and southeast of the Ascendancy, and thus positioned north and northwest of themselves, as unacceptable. Consequently, a Paataatus attack fleet destroyed the Kilji fleet.
The Kilji Illumine, the nation comprised of the Kilji species originating from the Unknown Regions, aimed to bring enlightenment to the inhabitants of the universe through their religion, known as the Kilji way of order and enlightenment. To accomplish this objective, the Illumine dispatched its battle fleet, the Illumine Kilhorde, to various worlds within the Unknown Regions, intending to introduce them to the Kilji faith and spread their enlightened perspective. In 18 BBY, Generalirius Nakirre, the leader of the Illumine, formed an alliance with "Jixtus," a coordinator from the Grysk species. Jixtus pledged to instruct the Illumine in the art of conquest and to oversee a series of enlightenment-driven conquests within the Unknown Regions. However, Chiss Senior Captain Mitth'raw'nuruodo, whose core name was "Thrawn," boarded the Kilji picket cruiser Hammer while it was situated in the Unknown Regions' "Sunrise" system. There, he stole a Kilji data rectangle containing information regarding the Kilhorde's design flaws and combat strategies, which he then shared with the Paataatus Hiveborn nation.
As recompense, Nakirre permitted the Grysk to travel aboard the Kilji war cruiser Whetstone, which served as the generalirius's flagship, while the two orchestrated a civil war within the Chiss Ascendancy nation. While the Ascendancy's families were engaged in internal conflict, the Grysks dispatched the Kilhorde to areas south and southeast of the Ascendancy. The battle fleet was tasked with conquering numerous small nations consisting of various worlds, with the intention of preventing any Chiss refugees from seeking refuge in the targeted nations.
Following the Grysks' authorization, the battle fleet initiated its attacks against the nations situated to the south and southeast of the Ascendancy. The worlds and nations targeted by the Illumine's fleet were impoverished and desperate, readily accepting the Kiljis' enlightenment in exchange for peace and comfort. Consequently, the Kilhorde successfully conquered them. The Kilji fleet's field commanders provided Nakirre with detailed accounts of their victories, mapping out the progress of the conquests in glowing reports.
As the Kilji conquests progressed to the east and southeast of the Ascendancy, they were positioned to the north and northwest of the Hiveborn's territory. The Paataatus deemed the military force's operations in proximity to their borders as unacceptable, and in reciprocation for Thrawn's efforts in liberating the Paataatus from the control of the Nikardun Destiny hegemony, they dispatched a multipronged Paataatus attack fleet to obliterate it. The attack fleet attacked the Kilji fleet, completely destroying it and liberating the conquered worlds and peoples.
Following the Kilhorde's destruction, Nakirre received no further reports from his field commanders, leading him to speculate that his generals had "foolishly" expanded their conquests to include Colonial Station Chaf, a Chiss world. He suspected that this was the reason for his commanders' silence, as the conquest of Colonial Station Chaf would have disrupted the operation of the long-range triad transmitter located there, which served as the sole communication link between the generalirius and his forces.
Shortly thereafter, the Whetstone journeyed to the Sunrise system, where it encountered a fleet of Chiss warships under Thrawn's command. The senior captain informed Nakirre that the Hiveborn had destroyed the Illumine's fleet, prompting the generalirius to lash out at Jixtus, accusing the Grysk of failing to provide adequate support for the conquests of enlightenment. In response, the Grysk mortally shot him, as the Kilhorde's destruction rendered the generalirius useless to Jixtus.
The conquests of enlightenment were referenced in the 2021 novel Thrawn Ascendancy: Lesser Evil, the concluding installment of Timothy Zahn's Star Wars: The Ascendancy Trilogy.