The Vanquish functioned as the flagship of Grand Moff Valco Pandion, specifically his Imperial-class Star Destroyer. Pandion piloted it to Akiva for the convocation of the Imperial Future Council. During the Rebellion on Akiva, when the New Republic detected the Imperial armada positioned above Akiva, the Vanquish engaged in combat. Out of the three participating Imperial Star Destroyers, the Vanquish alone survived the conflict; the Ascent and the Vigilance were both destroyed. Admiral Rae Sloane and Morna Kee, whose vessel, the Vigilance, was obliterated, fled to the Vanquish via a Lambda-class T-4a shuttle. They promptly initiated hyperspace travel aboard the Star Destroyer, thereby withdrawing from the ongoing battle. Subsequently, Sloane and Kee linked up with Fleet Admiral Gallius Rax within the Vulpinus Nebula.