The Kilji Overlords functioned as part of the governing body of the Kilji Illumine, which was the nation belonging to the Kilji species. These Overlords gave their approval to the choices made by the generalirius, who served as both the leader of the Illumine and the commander of its military force, the Illumine Kilhorde. In the year 18 BBY, when Generalirius Nakirre, the Illumine's leader, consented to go with his ally, "Jixtus," a Grysk agent from the warlike Grysk species, to seize control of other nations and disseminate the Kilji's ideologies, the Kilji Overlords confirmed that they were in agreement with his choice.
As they circled the Unknown Regions world Zyzek on Nakirre's Kilji war cruiser, the Whetstone, the generalirius came to the understanding that Jixtus's hidden identity, achieved by completely concealing his physical form, provided him with a strategic edge in negotiations over Nakirre. Nakirre's skin patterns revealed his feelings, providing his ally with insights that went beyond the Kilji's spoken words. Nevertheless, he recalled that the Overlords had endorsed his decision to journey alongside Jixtus, and he accepted his disadvantage.
The Kilji Overlords received a mention in the 2021 book Thrawn Ascendancy: Lesser Evil. This book is the concluding part of Star Wars: The Ascendancy Trilogy and was authored by Timothy Zahn.