The Bright Nebula Fleet served as a fleet within the Galactic Republic's naval forces, seeing action in a battle on Lokori amidst the Clone Wars. While the majority of the engagement unfolded outside the moons of Lokori, Separatist drop ship managed to bypass Republic defenses, deploying squadrons of Vulture droid starfighters into the atmosphere. For a duration of four local months, the skies were filled with ongoing air raids and intense combat extended into nearby space. As the Bright Nebula Fleet reinforced Republic forces, the Separatists mirrored this buildup with an equivalent number of ship.
Ultimately, the Separatists breached Republic lines at the same moment that Supreme Chancellor Palpatine announced his transformation into the Galactic Emperor and proclaimed the establishment of the Galactic Empire.
The canon novel Catalyst: A Rogue One Novel, penned by James Luceno in 2016, marked the first appearance of the Bright Nebula Fleet.