The Illumine Kilhorde functioned as the battle fleet and military force of the Kilji Illumine, which represented the nation-state of the Kilji species. It operated under the command of the Illumine's supreme leader, Generalirius Nakirre, aided by a group of generals and various field commanders. The Kilhorde journeyed to various worlds located within the Unknown Regions, aiming to spread the Kilji religion to the inhabitants. During 18 BBY, Nakirre formed an alliance with "Jixtus," a Grysk operative, who pledged to orchestrate a series of conquests of enlightenment to be executed by the Kilhorde. As part of their agreement, Nakirre granted the Grysk permission to travel aboard the Whetstone, a Kilji war cruiser that served as the generalirius's flagship.
While the pair instigated a civil war within the Chiss Ascendancy, the Grysks deployed the Kilhorde against smaller nations situated to the south and southeast of the Ascendancy. This was done to prevent Chiss refugees from seeking sanctuary in those nations as their own was consumed by internal conflict. However, Thrawn, a Senior Captain of the Chiss, obtained intelligence concerning the Kilhorde from the Kilji picket cruiser Hammer and shared it with the Paataatus Hiveborn. The Kilji's expansionist activities to the south and southeast of the Ascendancy also extended to the north and northwest of the Hiveborn. The Hiveborn considered the Kilji's presence near their borders unacceptable, leading them to dispatch a Paataatus attack fleet to annihilate the Kilhorde, effectively destroying it.
The Illumine Kilhorde was a substantial battle fleet that functioned as the military arm of the Kilji Illumine, the nation of the Kilji species. Its commander, Generalirius Nakirre, who also ruled the Illumine, regarded it as "mighty" and "unshakeable," despite underlying flaws in its design and combat strategies. It was composed of various starships.
Under the direction of Nakirre's generals and various field commanders, the Kilhorde explored the Unknown Regions of the galaxy, visiting numerous worlds and converting their inhabitants to the Illumine's Kilji way of order and enlightenment religion. In 18 BBY, Nakirre allied with "Jixtus," a coordinator from the warlike Grysk species, who promised to introduce the Illumine to the concept of conquest and guide the Kilhorde in a series of conquests of enlightenment. In return, Nakirre permitted Jixtus to travel aboard his flagship, the Kilji war cruiser Whetstone, while they worked to incite a civil war within the Chiss Ascendancy in the Unknown Regions.
During that year, the Whetstone journeyed to the Zyzek system in the Unknown Regions, where Nakirre confronted Mitth'raw'nuruodo, also known as "Thrawn," a Chiss Senior Captain in command of the Chiss heavy cruiser Springhawk. As the two cruisers prepared for combat following a heated exchange, Zyzek System Defense, responsible for protecting the Zyzek star system, dispatched several patrol ships to engage the two vessels. Nakirre considered destroying the newcomers, but ultimately decided against it, reasoning that such an action would result in death and prevent their enlightenment to the Kilji way, as well as deprive them of witnessing the "might" of the Kiljis before the Kilhorde visited their worlds. Subsequently, the generalirius departed Zyzek for the Ascendancy.
As the pair spread conflict among the Ascendancy's families, Jixtus and Nakirre's relationship deteriorated. In an unidentified star system within the Unknown Regions, Jixtus revealed the Shatter-class WarMaster FateSpinner, the Grysk flagship, which the operative boasted could obliterate the Kilhorde in a mere two hours. Jixtus's threat compelled Nakirre to comply with his ally's every demand. Shortly thereafter, Thrawn boarded the Illumine's Kilji picket cruiser Hammer and retrieved data concerning the Kilhorde's design and battle strategies, which he then shared with the Paataatus Hiveborn. After securing the Grysks' approval, the Kilhorde targeted smaller nations to the south and southeast of the Ascendancy, aiming to prevent Chiss refugees from seeking refuge in those territories.
These nations, comprised of impoverished and desperate worlds, lacked the means to resist the Kilhorde's aggression and were willing to embrace the Kilji religion in exchange for peace and security. Consequently, the Kilhorde's conquests proved successful. These conquests, occurring to the south and southeast of the Ascendancy, positioned them to the north and northwest of the Hiveborn. Considering the military force's operations near their borders unacceptable, the Paataatus dispatched a Paataatus attack fleet to destroy the Kilhorde, obliterating it and liberating the conquered worlds and peoples as a favor to Thrawn, who had previously freed the Hiveborn from the control of the Nikardun Destiny hegemony earlier that year. After Jixtus informed him that the Kilhorde targeted the smaller nations because they were unable to resist their attack, Nakirre contemplated murdering Jixtus. However, the generalirius speculated that Jixtus's fleet knew the whereabouts of the Kilji fleet, and decided against it.
As the fleet's field commanders had been sending him positive reports of victory, mapping their progress of their conquests, Nakirre grew concerned when communications ceased. He feared that his generals had "foolishly" extended their conquests to Colonial Station Chaf, a world within the Ascendancy, which would disrupt the operation of the world's long-range triad transmitter, the sole communication link between the Kilhorde and its generalirius. Soon afterward, Nakirre offered to deploy a number of the Kilhorde's vessels to assist Jixtus's fleet in its efforts to defeat Thrawn; however, Jixtus deemed it unnecessary, rejecting the generalirius's offer. Shortly after, the Whetstone traveled to an Unknown Regions system known as the "Sunrise" system, where Nakirre encountered Thrawn's fleet. The senior captain informed the war cruiser's commander that the Paataatus had destroyed his battle fleet, prompting Nakirre to lash out at Jixtus, who, in turn, murdered the generalirius, effectively ending the Kilhorde.
Generalirius Nakirre served as the Kilhorde's leader and commanding officer. Several generals enlightened to the Kilji way of order and enlightenment and a number of field commanders also commanded the battle fleet.
The Illumine Kilhorde made its debut in the 2021 novel Thrawn Ascendancy: Lesser Evil, the concluding installment of Timothy Zahn's [[Star Wars: The Ascendancy Trilogy|Ascendancy Trilogy.