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.
Finally, each Sovereign Protector would receive rudimentary training from Senior Dark Side Adepts (such as Arden Lyn) to wield the dark side of the Force—although not enough to provide independence or stoke ambition. The most exceptional Sovereign Protectors were eventually eligible for training as Dark Jedi.
Some of these armored and robed soldiers were charged with the personal protection of EmperorPalpatine, while others were deployed to guard Palpatine's interests throughout the galaxy, including the Imperial Citadel on the Deep Coreplanet of Byss, as well as other palaces and monasteries. A number of Sovereign Protectors were stationed aboard the Star DreadnoughtEclipse. 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.