Galactic Civil WarEdit
During the early days of the Galactic Empire, it was not uncommon for stormtroopers of the Guard to be led in combat by certain Field Commanders. These officers were often crucial to a victory. As such, they were usually kept in the rear of an invasion, or safely in an Imperial base.
However, when Alliance to Restore the Republic forces began to attack lightly defended imperial bases, often bypassing the main army, it became clear that the empire would need to defend their valuable commanders. As commanders were not trained in combat, the solution was to guard them with stormtroopers that would stay with them at all times.
The forces were rarely seen guarding other Imperial officers, and it is possible they were only used for this purpose. The were in many ways the equivalent to the Alliance Elite Guard.
In 4 ABY, Galactic Emperor Palpatine and Supreme Commander Darth Vader were killed over Endor aboard the Death Star II during the battle there. In the small successor state formed after the Empire dwindled from warlords, the Imperial Remnant formed an elite shock trooper unit known as the Imperial Elite Guard. They performed a similar function during the Second Galactic Civil War, protecting officers such as Admiral Gilad Pellaeon. However, the Elite Guard failed to stop Tahiri Veila from killing the admiral.
These soldiers were given the same training as standard Imperial stormtroopers. However, it is likely that they were given a higher emphasis on defense, in addition to operating in tightly knit squads. They were given the same equipment as Stormtroopers, Snowtroopers, and Sandtroopers, depending on the environment.