The 439th Legion functioned as an Imperial military organization within the Stormtrooper Corps during the era of the Galactic Civil War. Notably, it contained a scout trooper platoon whose members struggled to assimilate into the broader military structure. This difficulty stemmed from their open disdain for other troopers within the Imperial Military.
By the time 1 BBY arrived, which was not even a year after the Galactic Civil War commenced between the Rebel Alliance and the Galactic Empire, the 439th Legion had come to be primarily staffed by enlisted troopers who were Human recruits born naturally, largely superseding clone soldiers as the main fighting force of the Imperial Military. During approximately the same period, a light infantry platoon composed of scout troopers was reassigned to the 439th Legion while stationed on the planet of Byss. Despite their reputation as a well-equipped and competent division, these scouts found themselves unable to integrate socially within the 439th, quickly becoming a source of considerable friction between themselves and the rest of the unit's soldiers. While maintaining a strong sense of unity amongst themselves, they also developed a pattern of being extremely unpleasant and withdrawn towards anyone outside of the scout trooper program.
Beyond their obvious disrespect for other elements of the Stormtrooper Corps, the scout troopers started engaging in speeder bike races on their speeder bikes inside the Legion's barracks throughout the night, explicitly intending to disturb the sleep of the other troopers. The regular stormtroopers belonging to the 439th grew so irritated that reports suggested the scouts needed to be isolated from the remainder of the Legion for their own well-being.
The 439th Legion received a mention within the Scout Troopers' Databank entry featured in the PS3 and Xbox 360 iterations of the 2010 video game titled Star Wars: The Force Unleashed II.