In the year 18 BBY, the Paataatus Hiveborn nation, situated within the Unknown Regions, launched an attack against the Illumine Kilhorde. This fleet, belonging to the Kilji Illumine, had previously seized several smaller nations located to the north and northwest of the Hiveborn's territory as part of their conquests of enlightenment. The Hiveborn viewed the Kilhorde's actions near their borders as unacceptable. Consequently, a multifaceted Paataatus attack fleet was deployed with the mission of obliterating the Kilhorde, an action prompted after Chiss Senior Captain Mitth'raw'nuruodo provided the Paataatus species with crucial intelligence regarding the Kilhorde's design and battle strategies.
The Hiveborn successfully decimated the Kilji battle fleet and liberated the nations that the Illumine had subjugated. The annihilation of the Illumine's fleet led to the murder of Generalirius Nakirre by the Grysk named "Jixtus," who was allied with Nakirre. Jixtus determined that the destruction of the Kilhorde rendered Nakirre without value to him.
Back in 19 BBY, the Grysk operative known as "Jixtus" charged his Nikardun associate, General Yiv, and his Nikardun Destiny hegemony with the task of conquering the nations surrounding the Chiss Ascendancy in the Unknown Regions, including the Paataatus Hiveborn of the Paataatus species. While Yiv successfully conquered the Hiveborn, the Ascendancy reduced the Destiny to scattered remnants, one of which maintained control over the Hiveborn. In 18 BBY, a year later, the Chiss Senior Captain Mitth'raw'nuruodo, whose core name was "Thrawn," freed the Paataatus homeworld of Nettehi from the remnant's grasp.
Later that year, Jixtus formed an alliance with Generalirius Nakirre, the leader of the Kilji Illumine nation in the Unknown Regions. The Grysks authorized the Illumine's battle fleet, the Illumine Kilhorde, to advance against the smaller nations situated to the south and southeast of the Ascendancy. This was intended to prevent Chiss refugees from seeking refuge in those nations as Jixtus and Nakirre orchestrated a civil war within the Ascendancy. However, Thrawn retrieved data concerning the Kilhorde's design and combat tactics from the Kilji picket cruiser Hammer and subsequently shared this information with the Hiveborn. Given that the Kilji conquests were occurring to the south and southeast of the Ascendancy, they were positioned to the north and northwest of the Paataatus nation, a situation deemed unacceptable by the Hiveborn. Consequently, as a gesture of gratitude for Thrawn's assistance in liberating their homeworld, the Paataatus dispatched a multipronged Paataatus attack fleet to engage the Kilhorde.
Nakirre grew concerned when he ceased receiving reports of success from the Kilhorde's field commanders. This prompted him to speculate that his generals had "foolishly" expanded their conquests to include the Ascendancy's planet of Colonial Station Chaf. He feared an attack on the Chiss world would disrupt the operation of the planet's long-range triad transmitter. The generalirius reasoned that the lack of communication stemmed from his commanders disrupting the transmitter, which served as the sole link between them and Nakirre.
After Nakirre's Kilji war cruiser Whetstone arrived in the Unknown Regions' "Sunrise" system, it encountered a fleet of vessels under Thrawn's command. The senior captain informed Jixtus, who was aboard the Whetstone, that he had erred in assigning Yiv the task of conquering the Paataatus. He explained that he had liberated the Hiveborn, and the Paataatus were now grateful for his assistance. Upon learning from the Chiss that the Hiveborn had destroyed the Kilhorde as a favor to him, the generalirius lashed out at Jixtus, which led the Grysk to murder his ally, as the Kilji fleet's demise had rendered Nakirre useless.
This attack is referenced in Thrawn Ascendancy: Lesser Evil, the final book in Timothy Zahn's Ascendancy Trilogy, released in 2021.