I wasn't a stormtrooper commander in the Imperial Palace Guard for no reason.
TK-621, nicknamed "Omicron", was a clone stormtrooper in the Galactic Empire. Serving the Empire in the Stormtrooper Corps since 16 BBY, he was part of an experimental batch that initially had accelerated aging, but after reaching service age, slowed down and extended their lifespans. Though most clone stormtroopers were programmed to serve the New Order without question, his batch allowed more critical thinking. Nonetheless, Omicron carried out his orders well and had a reputation as a lethal shot. Along with that and his great strength, Omicron also possessed great tactical/strategical skills, and was promoted to Stormtrooper Commander because of it.
During the Imperial Period, he was part of the infantry attachment for a unit called 3rd Heavy Armor. Working around walkers a lot, Omicron learned who to drive the All Terrain Armored Transport and took the role of an Imperial Army Pilot in multiple battles. However, early in the Galactic Civil War, Omicron was assigned to 501st Legion, an elite unit of troopers who were considered to be among the Empire's best troops. By 1 ABY, he was reassigned to the 908th Legion, as the commander. The 908th was subservient to a female Emperor's Hand named Anya Inyri. They engaged the Alliance to Restore the Republic in many battles, but the unit he was in did not take part in the three most famous ones (Yavin IV, Hoth, and Endor). Toward the end of the War, he was assigned to the Imperial Palace Guard.
He continued to serve the Imperial Remnant, and Thrawn's Confederacy as well as reborn Palpatine's Dark Empire. He served in the 908th during the years of the Imperial Civil War. As he served the Remnant, Omicron was assigned to the Bastion Palace Guard. There, he was reunited with Anya, who also served it. Despite having a rather emotionless personality, Omicron fell in love with Anya during the Yuuzhan Vong War. The two married afterwards, and Omicron continued serving in the Guard. He later took a command position in the Stormtrooper Command.