Meki Ura, also known as Darth Plagueis, was a male Makai Dark Lord of the Sith. Plagueis mastered the art and science of midi-chlorian manipulation. Obsessed with eternal life, he experimented with ways to cheat death and create new life from the midi-chlorians. In his public guise as a Magister of the InterGalactic Banking Clan, Darth Plagueis backed the rise and fall of certain star systems, businesses, and crime lords, earning him many enemies and putting the Galactic Republic into turmoil.
One of Plagueis' greatest contributions to the history of the galaxy was training Darth Sidious in the ways of the Sith and the dark side of the Force, whom he incited to take control of the galaxy and bring about a new age of the Sith. For decades, he had helped Sidious, known publicly as Daishii Kann from Naboo, rise to the position of Senator and played a hand in his apprentice's election as the Supreme Chancellorof the Republic in 32 BBY. Together, they instigated the Yinchorri Uprising in 34 BBY, the Invasion of Naboo, and the war that would destroy the Jedi Order and the Republic in years to come.
Plagueis planned to be appointed co-chancellor of the Republic so that he might advise Sidious from the dark and devote himself to his own research. But his apprentice had other plans. Sidious, convinced that his master had outlived his usefulness, eventually killed the Makai in his sleep the night before his election and eventually rose to become ruler of the Galactic Empire.
Sidious later recounted the tale as The Tragedy of Darth Plagueis the Wise—an "old Sith legend"—to sway his son Korn to the dark side, though Plagueis himself remained a mysterious figure to the Jedi and their allies well into the time of the Galactic Alliance.