The Emperor's Royal Guard, sometimes referred to as the Imperial Royal Guard or Imperial Guard, was an elite unit of the Galactic Empire's armed forces tasked with the protection of the Emperor, Palpatine. Palpatine was almost never seen without a detachment of Royal Guards at his side, so much that they usually accompanied him to his bed chambers and his office within the Death Star. The exact number of Royal Guardsmen serving the Emperor was unknown, with speculations ranging from less than fifty to tens of thousands, although their numbers were estimated to be at least four hundred at any one point. Like the stormtroopers of the Stormtrooper Corps, the Royal Guards formed a military unit independent of the Imperial Military and answered directly to the Emperor.

(starwars.wikia.com/wiki/Emperor%27s_Royal_Guard)

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