Darth Sidious
Palpatine is a fictional character and the main antagonist of the Star Wars saga, portrayed by Ian McDiarmid in the feature films.
Palpatine first appeared as the unnamed Emperor of the Galactic Empire in the 1980 film Star Wars Episode V: The Empire Strikes Back, and was voiced by Clive Revill. He is an aged, pale-faced figure who wears dark robes. In Return of the Jedi, Palpatine (now portrayed by Ian McDiarmid) oversees the final stages of the war between the Rebel Alliance and the Empire, culminating in a confrontation with Luke Skywalker, in which Palpatine is ultimately destroyed.
In the films and the Expanded Universe, Palpatine is portrayed as cunning and deceptive in manipulating people and events to achieve his goals. Palpatine's principal desire is to have ultimate power. Palpatine presents himself in public to others as a modest, polite, and harmless person. However behind this public persona, in reality he is a ruthless megalomaniac.
In the prequel trilogy, Palpatine is a middle-aged politician of the Republic who rises to power through deception and treachery. As the Senator from Naboo and later the Chancellor of the Republic, he outwardly behaves like a well-intentioned and loyal public servant and supporter of democracy, yet underneath his affable public persona lurks his true identity: Darth Sidious, a Dark Lord of the Sith. As both Palpatine and Sidious, he sets into motion a series of events—including the Clone Wars—which ultimately destroys the Jedi Knights and the Republic, allowing him to usher in the Galactic Empire, a brutal authoritarian regime.
Since the initial theatrical run of Return of the Jedi, Palpatine has become a symbol of evil and sinister deception in popular culture.
Read more about Darth Sidious: Characteristics, Popular Culture