The Imperial Knights Lost Fleet was a fleet formed by Knight-Commander Bellatrix La Rouge during the Third Galactic Civil War. Originally amassed to serve as the naval force of the Imperial Knights-in-exile, with the Excalibur as its flagship, Rouge hid the entire fleet in an unknown location only known as Siege-1. Only Rouge, Ayumi Pallopides, and Commodore Barrel knew the location of Siege-1. With Rouge killed by Darth Illusia, and Operation Twilight killing Pallopides at HOMEFRONT and killing Barrel aboard Excalibur, the location was lost to the Imperial Knights. However, Rouge left clues with her son, K. Together with Athos, K and Athos sought out the missing fleet.