Darth Plagueis Darth Plagueis ( ) was a male Dark Lord of the Sith and the master of Darth Sidious . He acquired considerable knowledge in the field of midi - chlorian manipulation , but was ultimately betrayed and murdered by his own apprentice , in accordance with the " Rule of Two . " Sidious later recounted the tale of his master ' s demise to lure Anakin Skywalker to the dark side . Biography . Darth Plagueis was a male Dark Lord of the Sith who , at some point , chose Sheev Palpatine , a human from Naboo , as his apprentice . As master and disciple , Plagueis and Palpatine — who took the Sith moniker Darth Sidious — worked together , trying to unlock the secrets of immortality and to execute their order ' s long - percolating plan of supplanting the Galactic Republic with a new Sith Empire . According to Sidious , Plagueis was powerful enough that he could use the Force to influence the midi - chlorian s to create life and keep the ones he cared about from dying , a precious knowledge that awarded him the epithet of " The Wise . " Plagueis , however , also developed a belief that the Force could " strike back " at him for his power . In truth , he became so powerful that the only thing he still dreaded was losing his power . Ultimately , Plagueis ' only fear was bound to come true . At some point Sidious had learned everything he needed from his master . Moreover , he had acquired his own pupil in the Nightsister Mother Talzin ' s son , Darth Maul , a young Dathomirian Zabrak whom Sidious had kidnapped from Talzin when he was only a child . As the Rule of Two mandated that only two Sith — a master and an apprentice — could exist at any given time , one of them had to die . Now that he had no further use for a teacher , Sidious disposed of Plagueis , killing him in his sleep . With the death of Plagueis , Sidious not only gained the status of Master , but also acquired 11 - 4D , the late Sith Lord ' s multi - limb ed protocol droid assistant . Later , after taking Darth Vader as his apprentice , he reformed the Republic into the Galactic Empire and declared himself Emperor . In the years that followed his rise to Emperor , Sidious came to genuinely , if posthumously , appreciate Plagueis for the planner and prophet he had been . Sometimes , he mused about how his late master would have reacted when confronted with the trivial , day - to - day matters of Imperial politics . Behind the scenes . Darth Plagueis was first mentioned on - screen in the 2005 movie , the third installment in the prequel trilogy of " Star Wars " . Although Palpatine was never confirmed to be Plagueis ' apprentice in the movie itself , a link to the official encyclopedia on StarWars . com did refer to Sidious as having been " trained by Darth Plagueis . " The character was created by George Lucas as early as the first draft of " Revenge of the Sith " — dated April 2003 — and possibly earlier . His story was massively expanded upon in the 2012 novel " Darth Plagueis " , written by James Luceno . However , that story is part of the " Star Wars " Legends continuity , formerly known as the Expanded Universe , and therefore is no longer canon as of the 2014 reboot . The novel " Tarkin " , also by Luceno , includes a number of references to Plagueis and canonizes certain elements that had been introduced in the " Darth Plagueis " novel .