A member of the Kilji species, known by the designation "Vassal Three," was a Kilji vassal who adhered to the Kilji religious beliefs and served the Kilji Illumine, which was the government of the Kilji. This individual was stationed aboard the [Anvil], a Kilji war cruiser commanded by General Crofyp, in 18 BBY. The Anvil, along with the Kilji picket cruiser Hammer, which comprised Crofyp's task force, journeyed to the Unknown Regions Rapacc system to extract refugees. However, they were confronted by the [Aelos], a Nikardun blockade frigate under the control of the Paccosh. Crofyp issued a demand to the Aelos, requesting permission to retrieve the refugees hidden amongst the Paccosh, but this request was denied by the commander of the frigate.
Following this refusal, Crofyp instructed Vassal Three to eliminate the frigate should it maneuver into the path of the Anvil. The Anvil then repositioned itself, but the Aelos did not initiate an attack. Subsequently, the Chiss heavy cruiser [Springhawk] arrived in the system and destroyed the Anvil, while the Hammer escaped into hyperspace.
The character of Vassal Three made their debut appearance in Thrawn Ascendancy: Lesser Evil, a 2021 novel and the concluding installment of the Star Wars: The Ascendancy Trilogy penned by Timothy Zahn.