The Indomitable, a MC140 Scythe-class battle cruiser, served the Galactic Alliance beginning no later than 130 ABY.
During the Sith–Imperial War, the Indomitable acted as the flagship for Admiral Gar Stazi and represented the Galactic Alliance's might. Following the Battle of Caamas, where the Empire defeated the Galactic Alliance, it became the flagship of the Galactic Alliance Core Fleet.
The Indomitable's final battle occurred at the Battle of Mon Calamari, after seven years of assaults against Darth Krayt's Galactic Empire. After being outmaneuvered by Stazi, Admiral Dru Valan gave the order for his battered fleet to obliterate the Indomitable at any cost. After Stazi ordered the rest of the Alliance fleet to flee the system, he commanded the ship to be evacuated so that he could ram it into the Mon Calamari Shipyards, but Rogue Leader Jhoram Bey knocked him unconscious. Jaius Yorub, the ship's captain and Stazi's second-in-command, then piloted the ship into the shipyards. While he died in the attack, he succeeded in destroying one-third of the shipyards and damaging another quarter.
Later, the Imperious-class Star Destroyer Alliance took the Indomitable's place as the flagship.