The 481st Legion served as a unit within the Grand Army of the Republic near the conclusion of the Clone Wars. During 19 BBY, it participated in the execution of Order 66, a clandestine order that compelled clone troopers to execute their Jedi allies. As part of this directive, segments of the 481st Legion were sent to the planet Ilum with the mission to safeguard the Jedi Temple located there and eliminate any Jedi who had survived the initial attacks.
Following the Galactic Republic's transition to the Galactic Empire under the rule of Emperor Palpatine, the 481st Legion was withdrawn and brought back to its original unit. Subsequently, a joint Imperial Army garrison along with an Imperial Navy battle group took its place, establishing a blockade.
The roleplaying supplement Nexus of Power, released in 2016 by Fantasy Flight Games, included a reference to the 481st Legion.