Darth Plagueis (pronounced /‘pleɪɡ.əs/) was a Force-sensitive Muun male Dark Lord of the Sith and the master of Darth Sidious. Plagueis lusted for immortality, believing the secret laid in science, so worked with his apprentice, conducting research into bioengineering and experimented with his ability to influence the midichlorians to create life. He truly acquired considerable knowledge of the Force, 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 the Jedi Knight Anakin Skywalker to the dark side of the Force.
Darth Plagueis was a wise Dark Lord of the Sith who possessed a vast knowledge of the dark side of the Force. He was a meticulous planner, who tried to accomplish the Sith’s goal to replace the Galactic Republic with a Sith Empire. Due to his powers, he also became paranoid, believing that the Force could «strike back» against those who sought to meddle with the very fabric of both the physical and cosmic realms.
Obsessed with achieving immortality, Plagueis strived to discover the path towards becoming an eternal being alongside his apprentice Darth Sidious and rule together for thousands of years, and believed the secret to it laid in science. While Plagueis became afraid of losing his power, he never expected his apprentice to be the reason he would lose power. Ultimately, Plagueis underestimated Sidious, who betrayed and murdered him when he least expected it. Though Plagueis did not live to achieve his goals, Sidious succeeded to survive his death, but given that his transfer was imperfect, he asked himself if maybe Plagueis got the last laugh after all at his failure.