A Kilji known as "Vassal One" served the Kilji Illumine, the government of the Kilji species, as a Kilji vassal and followed the Illumine's religious beliefs. In 18 BBY, they served aboard the Kilji war cruiser Anvil under the Illumine's General Crofyp. After Crofyp's task force, consisting of the Anvil and the Kilji picket cruiser Hammer, traveled to the Unknown Regions' Rapacc system to retrieve a group of refugees, it was confronted and prevented from doing so by the Paccosh-commandeered Nikardun blockade frigate Aelos.
Following the confrontation, Crofyp ordered Vassal One to move the Anvil past the Aelos along the frigate's starboard. After the Anvil had been positioned, the Chiss heavy cruiser Springhawk also arrived in the star system and attacked and destroyed Crofyp's cruiser.
Vassal One appeared in the 2021 novel Thrawn Ascendancy: Lesser Evil, the final volume in the Star Wars: The Ascendancy Trilogy written by Timothy Zahn.
Vassal One appeared in the 2021 novel Thrawn Ascendancy: Lesser Evil, the final volume in the Star Wars: The Ascendancy Trilogy written by Timothy Zahn.