The Vanguard was commanded by a female officer named Captain Inadi, and was assigned to Task Force Aster, part of the New Republic Fifth Fleet. Accompanying the task force command ship Indomitable in a patrol of part of the Koornacht Cluster, the gunship encountered Yevethan Aramadia-class thrustships at the Battle of ILC-905.
Vanguard was initially assigned to flank the larger Indomitable during their pass through the ILC-905 system, then ordered to ahead to scout beyond the horizon of the planet known as Prildaz, where the gunship's sensors detected the former Imperial shipyard Black Nine, along with the two defending warships Tholos and Rizaron, and a recently docked Yevethan cargo vessel.
The Vanguard promptly came under fire from both Yevethan warships, with her shields weakening under the intense barrage from their turbolasers. One of the gunship's own laser cannons misfired and exploded, and the particle shields collapsed under a missile salvo from Rizaron.
The Indomitable entered the combat at this point, drawing away turbolaser fire from Tholos, while two successive waves of K-wing bombers were dispatched to assist Vanguard against Rizaron.
In an attempt to assist the K-wings, the Vanguard launched her remaining CM-9 concussion missiles, but the midships battery malfunctioned, causing further damage to the gunship. The thrustship responded with a second missile salvo of her own. The first missile of this salvo took out three engines and the power in the gunship's aft section, and Captain Inadi ordered the crew to abandon ship, but moments later two more missiles impacted, destroying the bridge and causing a violent explosion.
The Vanguard disappeared from the sensors of the Indomitable and the accompanying New Republic fighters, and was eliminated from the battle.