The Civil War had split the Empire in two, with the True Empire led by the so-called Emperor Palpatine "reborn". Based from Mon Calamari, the True Empire waged a war across Imperial-held territory with the goal of striking into and capturing the Core, held vigorously by the Empire.
Venixun was chosen as the ideal foothold to breach the Core. Located at the end tip of the Tarkin Corridor, it was sparsely defended and considered low importance to most Imperial strategists. A fleet led by Admiral Javert cut across the Inner Rim and, using a series of routes known only to Imperials, managed to launch a sneak assault on Venixun. Sieging the world and blockading it, the True Imperials seized control over the system. The Empire, fearing the loss of Venixun could mean the loss of the entire Corridor, quickly dispatched a small response force spearheaded by the HIMS Tormentor and Admirals Kendal Osbourne and Salin Fawzy.
The attack was repulsed by the True Imperials and the Admiral Javert fully occupied the system. The Empire pulled back to Guritsan to regroup and recall forces to mount a proper counter-attack. A second attack was mounted a month later as a delaying action to slow the rebels until more Imperial reinforcements could be pulled to the Core. The attack was moderately successful, destroying a rebel-held battlestation in orbit, but the Imperials were unable to break through True Imperial defenses.
Finally, Osbourne launched a third assault against Venixun. Having assembled a large fleet, the Imperials were able to break through Javert's defenses; success, however, was largely due in part to Javert being forced to recall many of his warships in an effort to defend Mon Calamari from a New Republic-Griffon Alliance joint attack. With its forces diverted, the Imperials were able to defeat the would-be usurpers. Javert retreated with his survivors, although the majority of his army was destroyed; rather than surrender, the rebel troops detonated a nuclear device that took out many Imperial units with it.
Venixun was liberated and thus the Tarkin Corridor was secured. The Civil War would end several months later in a sweeping Imperial victory.