An Imperial Sovereign Protector during Operation Shadow Hand
The uniforms of the Sovereign Protectors were similar in appearance to the standard garb of the Emperor's Royal Guard, although with several distinctions. Namely, they possessed a black chest-plate and gauntlets, their helmets' front was colored black while the rest was red, and they wore a black cape. In some cases, they wore ornate armor with hoods and a scythe-like force pike. They were led mostly by a Champion picked by the Emperor, and they directly answered to the Emperor alone.
Only the best of the elite Emperor's Royal Guard were specially chosen to become Sovereign Protectors. They endured years of selection procedures and training aimed at achieving perfection in soldiering. Extreme standards were set for combat fitness, stamina, strength, dexterity, mental acuity, reaction time, loyalty and intelligence. Their combat training included the use of heavy blaster pistols and the deadly double vibroblade. They also had access to Emperor's Royal Guard TIE/IN starfighters, and were often sent on extremely vital missions.
A Royal Guard Champion
Some of these armored and robed soldiers were charged with the personal protection of Emperor Palpatine, while others were deployed to guard Palpatine's interests throughout the galaxy, including the Emperor's Citadel on the Deep Core planet of Byss, as well as other palaces and monasteries. A number of Sovereign Protectors were stationed aboard the dreadnought Eclipse. They were typically organized into regiments of four hundred individuals.
The best known of the Sovereign Protectors was the treacherous Royal Guardsman Carnor Jax, who was promoted to the rank in 11 ABY at the instigation of Imperial Ruling Council member Sarcev Quest. Though Palpatine remained unaware, Jax and Quest were in fact leading a conspiracy to overthrow him—Jax, indeed, was an aspirant Sith Lord, who trained as the apprentice of Lumiya.
At least two Sovereign Protectors were tasked with guarding a vital Imperial data center on Sullust, escorting a Lambda-class T-4a shuttle to the facility.