Over the course of the Clone Wars, the Red Guard gradually supplanted the Senate Guard and its elite sub-unit, the Senate Commandos, as the chancellor's bodyguards. The origins of the crimson-clad Royal Guard dated back to the time of the Separatist Crisis, when Supreme Chancellor Sheev Palpatine crafted an order of protectors, named the Red Guard, that stood apart from the cerulean-clad Senate Guard during the Galactic Republic's twilight. The Imperial Royal Guard were also occasionally assigned to provide protection to members of the Imperial Ruling Council and Darth Vader.
In addition to strict requirements of size, strength, intelligence, and loyalty, only the most skilled soldiers in the Imperial Military qualified for duty in the Royal Guard. The Emperor's Royal Guard, also known as the Imperial Royal Guard, the Imperial Guard, or simply the Royal Guard, and under the Galactic Republic as the Red Guard, was an elite unit whose members served as personal bodyguards to the Galactic Emperor. Out of millions of soldiers, they are unsurpassed.' ―Korin Pers, to Lando Calrissian The Emperor's personal protectors-handpicked from the very best of his forces.