Darkseid, Galactus, the Spectre, Dormammu, Molecule Man, Doctor Doom, Thanos, etc…. they are far more evil than Palpatine could ever hope to be.
Whether as the Emperor, the Sith Lord, or the Supreme Chancellor, the villain consistently proves his evil through actions and quotes. Genius remarks, sickening declarations, goosebump-inducing exchanges, Palpatine produces them all, and they all prove that he is Star Wars' evilest villain.
Tarkin was the embodiment of Palpatine's desire to rule by fear and was put in charge of the Death Star project. In many ways, Tarkin was more ruthless than Palpatine.
1. Emperor Palpatine. Darth Sidious infiltrated the heart of the Republic and twisted it into the Empire, sparked a terrible war that engulfed the entire galaxy in fire and ash, corrupted once-noble Jedi to his cause, and executed Order 66 to erase the Jedi Order from existence.
The Emperor Is Worse!
There is also the fact that Anakin wasn't born evil, and was only lured to the Dark Side through his loved ones. Meanwhile, Palpatine was already inherently evil as a child and wanted power for power's sake.
Darth Sidious, also known as the Emperor and Supreme Chancellor Palpatine, is not just the evilest Sith in Star Wars (arguably in both canon and Legends) but the evilest villain overall, deemed so thanks to his irredeemable actions throughout the Skywalker saga and surrounding content.
The dark side of the Force is a pathway to many abilities some consider to be unnatural, and Sheev Palpatine is the most infamous follower of its doctrines. Scheming, powerful, and evil to the core, Darth Sidious restored the Sith and destroyed the Jedi Order.
Anakin Skywalker, aka Darth Vader, is no doubt the most famous Jedi who turned evil in the Star Wars Universe.
DARK SIDE FRIDAY - Did you know Palpatine feared Qui-Gon Jinn? Palpatine was immensely powerful and he could see the future which made him very confident about pretty much anyone who stood against him. So why Qui-Gon Jinn?
As the grandson of Anakin Skywalker (on his mother's side), one of the most powerful Force users in the galaxy, Kylo Ren has the appropriate bloodline to destroy Palpatine. It was a redeemed Anakin Skywalker who killed Palpatine the first time, and the same midi-chlorians flow through Ren's veins.
Having covertly turned Kylo Ren—Anakin's grandson and Luke's nephew—to the dark side, Palpatine orders Ren to find and kill Rey, the last remaining Jedi and Palpatine's paternal granddaughter. Palpatine is ultimately defeated and destroyed by Rey.
when he promised Anakin that he could teach him. to save Padme through the power of the Dark Side, Palpatine was just blatantly lying. as Anakin became his apprentice, he revealed that he was lying when he said this. the Cheat Death is a power only one has achieved.
The surprise, however, was that Palpatine should betray Dooku in favor of Anakin Skywalker, who Dooku looked at with a sense of distaste and condescension. He got revenge after a fashion, though, denying Palpatine the treasures he would have loved to get his hands on.
But the record Sith-killer is actually Darth Bane himself. Darth Bane, founder of the Rule of Two, killed more Sith than any Jedi in the history of the Star Wars galaxy. Thousands of years ago, a schism among the Jedi Order led to the creation of a new faction - one devoted to the dark side of the Force.
As Supreme Commander, Darth Vader was the ranking leader of the Imperial Military.
Darth Sidious
Darth Sidious is easily the most powerful Sith to ever live. He was able to almost single-handedly start a war, take control of the Senate, convert countless people including Anakin Skywalker to the dark side, overthrow the Jedi, and become emperor of the Galactic Empire.
It was Barriss herself who orchestrated the bombing and framed Ahsoka. Anakin dueled Barriss on Coruscant, and eventually placed her under arrest. Brought before a military tribunal led by Governor Tarkin, she admitted her guilt, but held steadfast in her belief that the Jedi and Republic had lost their way.
Galen was secretly trained as a Sith Lord apprentice to Vader, but returned to the light side and the Jedi. Galen Marek is the only one who came close to destroying the Sith Lord, thanks to his vast knowledge of Vader's fighting tactics through the many hours they trained together.
As a Sith Marauder in the Great Sith War, Sion fought for Exar Kun's Sith Empire until the day he was struck down. Rather than die, though, Sion found that by calling on his pain, anger, and hatred, he could rise from certain death and achieve immortality, at the cost of all-consuming agony.