A clash transpired in the locales of Vun'Hanna and the Twilight Void, situated within the Unknown Regions of the galaxy, pitting the forces of the Chiss Ascendancy against the Praetorite Vong. This conflict occurred around 27 BBY, culminating in the defeat of the Yuuzhan Vong combatants.
Originating from extra-galactic space, the Yuuzhan Vong had initiated scouting missions and begun settling along the edge of the galaxy to prepare for their impending invasion, starting as early as 32 BBY with their assault on Zonama Sekot. By 27 BBY, a small reconnaissance force from the Yuuzhan Vong encountered a Chiss force under the command of Admiral Ar'alani, and launched a swift offensive. The Yuuzhan Vong fleet was ultimately annihilated after its aggressive initial strike.
Soon after this engagement, Force Commander Thrawn's encounter with the Bargain Hunter sparked concerns that the Galactic Republic and the Yuuzhan Vong were collaborating in an invasion against the Chiss Ascendancy. When Special Task Force One arrived in the Unknown Regions and Kinman Doriana leveraged the potential threat of Jedi falling into Yuuzhan Vong hands as justification for destroying the Outbound Flight, Thrawn, aware of the Chiss's struggles against the limited Yuuzhan Vong scouting party, reluctantly endorsed the plan.
Years later, as the Yuuzhan Vong War began, Panha referenced this early skirmish to Sarkkin. In 55 ABY, the author Lenang O'Pali made mention of the battle at Vun'Hanna and the Twilight Void in their publication titled Mitth'raw'nuruodo Reconsidered: A Patriot's Perspective.