The 501st later became a Stormtrooper unit following the rise of the Galactic Empire. They mostly fight Harch Admiral Trench and his group, the New Confederacy of Independent Systems, in an attempt to keep peace through the galaxy.
Defending the ConquerorEdit
The 501st was called in to defend the modified Imperial-I class Star Destroyer the Conqueror, as it was taking heavy damage from the New Confederacy of Independent Systems' fleet. When Trench boarded the Conqueror and brought aboard an army of Corporate Alliance Tank Droids, Armored Assault Tanks (including his own), and many B1 Battle Droids and B2 Super Battle Droids, the 501st confronted them in a massive battle in which they brought in many AT-STs and TIE Crawlers. Stormtrooper Commander Appo, who led the 501st for this battle, ordered for the 501st Stormtroopers to destroy any droid that got near them. Though the droids did blow up a few AT-STs, the 501st clearly had the upper advantage.
That advantage was lost, however, after TK-33 called in the Platoon Attack Crafts to drop off more reinforcements, which totaled to 224 battle droids. The 501st fought back,but majority of their forces were depleted and all of their AT-STs and TIE Crawlers were destroyed. Angry, Commander Appo ordered the forces to retreat, but he told two 501st Scout Troopers to stay behind in order to guard the communications room. not long after Appo and the remaining 501st troopers left, Trench's forces killed the men inside and started to plan on how to get to the bridge of the ship, as well as finding the reactor core.
Meanwhile, Appo and the rest of the 501st had to tell the Emperor that they had failed, and the Emperor was not happy with them. Unbeknownst to them, they were being watched by the Commando Droids that had hid in the ventilations shaft.