Palpatine Essay
Of all the mystics and shamans and Jedi and Sith that have been portrayed in the mythos, there is no individual whose knowledge of the Force comes close to registering to that of Darth Sidious. The Dark Empire Sourcebook states that, upon his ascent to Galactic Emperor, Palpatine “gathered the greatest works [of Force knowledge] from over a million worlds” and “studied the Force in all its guises throughout the galaxy, whether it was the shamanism of the Jarvashqinne or the tales of the Tyia,” and that he had “long ago gone beyond any knowledge to be found in the recovered teachings of the Krath and Heresiarchs.” The New Essential Guide to Characters mentions that Palpatine had studied the Sorcerers of Tund prior to their destruction, particularly the adept Rokur Gepta. Many may be unfamiliar with these four esoteric Force cults, so a brief overview shall be provided.The Jarvashqinne and Heresiarchs are easily the two most obscure references. The Complete Star Wars Encyclopedia states that the Jarvashqinne is “a term that described both a religion that worshipped individuals who had mystical powers, as well as the shaman-like priests who wielded those powers, which were much like the control of the Force,” and that the Heresiarchs were “one of the many religious sects formed on the basis of Sith lore and teachings.” The same source concludes that the Krath was “a secret society founded by dark side dabblers and spoiled aristocrats Aleema and Satal Keto some 4,000 years before the Galactic Civil War in the Empress Teta star system,” and that it “developed into a dark side magical sect” before “being destroyed by several Jedi Knights.”
The Sorcerers of Tund was a “mysterious and ancient sect once based on the planet Tund,” that “traced their origins back to the Sith Empire,” according to the Complete Star Wars Encyclopedia. The New Essential Chronology and the Essential Guide to the Force conclude that the Sorcerers’ teachings were based on “archaic interpretations of original Sith doctrine,” which served to attract Emperor Palpatine’s interest. Though the extent of the Sorcerers’ power has not been explored, the Essential Guide to the Force mentions that they were frequently visited by Jedi recruiters and periodically asked to join the Order, “but the sorcerers—some of whom demonstrated powers at least as great as those of the Jedi recruiters—declined.”
During his many decades as the reigning Sith Lord, Palpatine acquired an unimaginable wealth of knowledge. Star Wars: Complete Locations mentions that his headquarters within the Chancellor Palpatine Surgical Reconstruction Center contained “archives, Sith holocrons, and other artifacts,” an “environmentally controlled display case for Sith scrolls,” and a “massive Sith holocron uncovered on Korriban.” After the execution of Order 66, the Jedi Archives on Coruscant were “raided by Emperor Palpatine and his Dark Side Adepts,” according to the Complete Star Wars Encyclopedia. The Dark Empire Sourcebook mentions a “full library of Dark Side texts” within Palpatine’s Citadel on Byss and the Complete Star Wars Encyclopedia’s entry on the same Citadel reveals that it was home to “libraries of dark side tomes” and “dark side alchemical laboratories.”
According to the Complete Star Wars Enyclopedia, page 51, a holocron was “a recording device used by the ancient Jedi Knights and Sith Lords to hold the teachings and lore needed to maintain the Jedi and Sith Orders.” The same source states that Emperor Palpatine “collected all manner of holocrons—both Sith and Jedi alike—in order to garner new information about use of the Force.” Palpatine’s subsequent raid of the Jedi Archives yielded the “restricted holocrons” which contained the deepest secrets of the greatest Masters of the Force,”—the ones desperately sought by Anakin Skywalker shortly before the rise of the Empire, which he intended to use to save his wife, Senator Padme Amidala, from inevitable death.
One of the notable holocrons in Palpatine’s clutches was the Tedryn Holocron (referred to by the New Jedi Order as “the Jedi Holocron”), which Palpatine claimed had been given to him by Jedi Master Ashka Boda, who was murdered by the Emperor at the end of the Clone Wars. This holocron would be stolen from Palpatine by Leia Organa Solo during the events of Operation Shadow Hand and subsequently destroyed by the spirit of ancient Sith Lord Exar Kun (The Essential Guide to the Force).
Another notable holocron that found itself in the Emperor’s grip was the Telos Holocron, recovered by the New Jedi Order during the so-called ‘Second Galactic Civil War’. This holocron in particular was of interest to the Jedi, due to the fact that Palpatine himself was the ‘gatekeeper’—the personage who functioned as the holocron’s archivist. Subsequent analysis of the Telos Holocron included a tour of the dark side, with Palpatine’s simulacrum functioning as a guide to the holocron’s audience, featured within the New Essential Guide to the Force. Within included entries from relatively obscure Sith Lords such as the ancient Ajunta Pall and Brotherhood of Darkness disciple Seviss Vaa to the more infamous and notorious Sith Lords such as Darth Bane and Darth Revan. Palpatine would periodically offer addendums to his predecessor’s work, correcting them or offering corroborative observations. The New Essential Guide to the Force also confirms many details about the Emperor’s knowledge of the Force and locations of Force relics.
An entry by Seviss Vaa conclusion that “many prominent Sith worlds—including Ziost, Khar Delba, and Khar Shian—went the way of Ashas Ree, as all were largely stripped of their relics by Republic forces after the Great Hyperspace War,” inciting this rebuttal from Palpatine’s simulacrum.
“Regarding Seviss Vaa’s descriptions of the worlds in Sith space, I can only assume he either lied about his visits to Khar Delba and Khar Shian or that his powers of observation were sorely lacking, as I discovered valuable relics on both worlds.”
The Emperor’s simulacrum revealed his knowledge of the works of “an ancient Jedi consular named Kla” who “turned to the ways of the Sith and became the gatekeeper for a most enlightening Holocron, which found its way into [his] possession.” He would go onto accredit Kla with “an encyclopedic knowledge of the Sith Empire under Naga Sadow,” and “although [Kla] didn’t always cite his sources, some of his knowledge may have been gained from a Sith Holocron kept by the Jedi Master Odan-Urr on Ossus,” indicating that Palpatine had acquired relics from the Jedi headquarters there.
The Dark Side Sourcebook cites “Sith alchemy” as being a practice that only the most powerful adepts can master. Palpatine’s simulacrum makes reference to the teachings of Naga Sadow, “one of the most powerful Sith alchemists” of the Sith Empire, “who left detailed records of his Holocron [Palpatine] came across some years ago.” Palpatine would later conclude that Sadow was “far too generous with his knowledge.”
The Dark Empire Sourcebook makes mention of the Emperor’s Dark Side Compendium, which the Complete Star Wars Encyclopedia defines as “an encyclopedia of dark side lore that was being written by the reborn clone Emperor.” The same source mentions that the Compendium, when completed, would have spanned several hundred volumes. The Emperor managed to complete only three before being destroyed by Luke Skywalker and his fledgling new Jedi Order in 11 ABY.
Given ample analysis of the various characters throughout canon, the only obvious conclusion is that Emperor Palpatine’s knowledge of the Force far exceeds that of any other being in terms of scope and scale. There is none who come close. Indeed, the Dark Empire Sourcebook provides an assessment of Darth Sidious’s knowledge in just two sentences:
“Palpatine has spent decades studying the most arcane and esoteric Jedi disciplines. It is believed that he has mastered nearly all the known powers, previously unknown powers, and devises new ones at his pleasure.”
Comparing Luke and Palpatine in the area of Force knowledge is absurd; based on what you've given me, it's a definite curbstomp in favor of the Emperor.