The Valiant, a Thranta-class War Cruiser, shared a lineage with the cruisers Courage and Fidelity. Following Alderaan's demilitarization after the Clone Wars, the Valiant, alongside its sister vessels, was tasked with guarding the Alderaanian War Frigate Another Chance. This frigate had been repurposed into an armory ship, responsible for transporting the surrendered weaponry of Alderaan's military away from the planet.
Though the escort ships' navigational systems were programmed to follow Another Chance into hyperspace and protect it, the Valiant became detached from the convoy. It subsequently lost the transponder signal originating from the armory ship. Unable to fulfill its designated mission, the war cruiser's automated protocols directed it back towards Alderaan, in anticipation of receiving revised directives. However, the destruction of Alderaan meant these updated orders would never materialize.
The cruiser persisted within the debris field known as the Graveyard of Alderaan until 7 ABY. At this point, its systems reacted to the IFF beacon emitted by Tycho Celchu's X-wing during the Battle of the Graveyard, leading it to engage the Corrupter in defense of Celchu.
During this period, Rogue squadron was operating independently, without the formal authorization of the New Republic government. Consequently, they opted to utilize identification signatures linked to their respective home planets, instead of the standard New Republic frequency. Celchu, being a native of Alderaan, chose to employ a pre-disarmament military frequency, which coincidentally matched the beacon employed by Another Chance. The droid crew aboard the Valiant interpreted this as an assault on the vessels they were programmed to safeguard, despite the discrepancy in vessel classes associated with the beacon.
Following the battle, the Rogues commandeered the war cruiser, transporting it to their base within the Yag'Dhul system. After some modifications, they were able to deploy it to great advantage in the final stages of the Bacta War against Ysanne Isard.
Aril Nunb, a Sullustan and the sister of Nien Nunb, was appointed as the ship's commander. This decision came after Emtrey was facetiously suggested as a potential candidate, and Booster Terrik had declined the position. The warship later participated in the conflict against the Super Star Destroyer Lusankya over Thyferra, where it targeted the Star Dreadnought's primary propulsion systems. Nunb continued to command the ship after this engagement.