The character was first mentioned on-screen in the 2005 film Star Wars: Episode III – Revenge of the Sith, in which Palpatine frames his life and death as a "legend" to pique Anakin Skywalker's curiosity about the dark side of the Force.

The character of Darth Plagueis was conceived by George Lucas as early as the first draft of the screenplay for Star Wars: Episode III – Revenge of the Sith (2005), or possibly earlier.

[3] For the Disney+ miniseries The Acolyte (2024), showrunner Leslye Headland decided early on to feature Darth Plagueis in the first season finale due to her interest to see the character debut in live-action media.

Palpatine explains that Plagueis was so powerful and wise, he had mastered the dark side of the Force to such an extent that he could cheat death and create life; unnatural abilities which are unknown to the Jedi.

During the final episode of the season, he made a small cameo appearance from a distance as he watches his apprentice, “Qimir”/The Stranger and former Jedi, Osha, leave the planet to find latter’s twin sister, Mae, and her former master, Sol.

[12][13][14] Star Wars Legends literature elaborates on Plagueis' life, apprenticeship under the Bith Sith Lord Darth Tenebrous, and mentorship of Palpatine, up until his death at the latter's hands.

According to the 2005 book Star Wars: The Ultimate Visual Guide, Plagueis had also discovered the ability to retain one's identity in the Force while becoming one with it, but this way of surviving death did not appeal to him, as he was mainly concerned with the material world.

Plagueis had possibly initiated his experiments before being murdered by his apprentice Sidious (which would have happened at some point between 52 and 46 years before the events of A New Hope), and there was evidence to believe Anakin Skywalker's virginal birth was the result.

Sidious failed to replicate Plagueis' way to prevent death, and was forced to rely on clone bodies to hold his spirit as shown in Dark Empire comic book series.

The novel covers the later life and machinations of Darth Plagueis (born Hego Damask II), over a roughly fifty-year period pre-dating and culminating concurrently with the climax of The Phantom Menace.