The Nikardun conquests, occurring within the confines of the Unknown Regions, were masterminded by General Yiv of the Nikardun Destiny. His objective: to seize control over various territories within the Chaos. Though Yiv successfully brought several factions under his control, either through conquest or alliance, the interference of the Chiss Ascendancy, spearheaded by Senior Captain Mitth'raw'nuruodo, ultimately thwarted his ambitions and led to the collapse of his plans.
Following a Nikardun attack targeting a refugee starship that had entered Chiss space, Captain Thrawn, aided by Admiral Ar'alani, initiated an investigation. This investigation uncovered Nikardun Destiny forces operating within the Rapacc system. Through multiple engagements with Nikardun forces and their allies, Thrawn gathered intelligence regarding General Yiv and his regime. Ultimately, Thrawn outmaneuvered the Nikardun in a battle fought near Primea, the homeworld of the Vak. Yiv was captured by Thrawn, becoming a prisoner of the Chiss Ascendancy. With Yiv gone, no one was able to take his place and fix the damage Thrawn had done to their empire, and the Nikardun conquests subsequently disintegrated.
The Ascendancy, having interrogated the captured Yiv, obtained information regarding the locations of remaining Nikardun forces. After being sufficiently convinced of the danger posed by these remnants, the Syndicure authorized the Chiss Expansionary Defense Fleet to "bend" the protocols prohibiting pre-emptive strikes and pursue them in what became known as the Nikardun campaigns. Two months following the battle over Primea, the Chiss were engaged in the mission to the Vak Combine and believed the Nikardun campaigns were nearing completion.
The Nikardun conquests formed the central storyline of the 2020 novel Thrawn Ascendancy: Chaos Rising, penned by Timothy Zahn. Furthermore, they laid the groundwork for the plot to destroy the Chiss Ascendancy, which served as the primary narrative of Chaos Rising's 2021 sequel, Thrawn Ascendancy: Greater Good. Greater Good revealed that Haplif, an agent of the Grysk Hegemony, incited the Nikardun Destiny to launch the attack at the edge of the Dioya system as a means of diverting the Chiss's attention from the civil war he had orchestrated on the planet "Sunrise."