Yes, Palpatine is often considered one of the most manipulative villains. His schemes and political machinations in the Star Wars universe are incredibly complex and far-reaching.
I don't think so. There are many other characters in fiction who could be considered equally or even more skilled manipulators.
One of the most famous manipulative women in fiction is Scarlett O'Hara from 'Gone with the Wind'. She used her charm and wits to get what she wanted, like manipulating Rhett Butler into marrying her. She was manipulative in the sense of trying to secure her own future and the future of Tara, her family's plantation, during a very difficult time.
One could argue that Voldemort from the Harry Potter series is a very strong contender. He is responsible for countless murders, including the death of Harry Potter's parents. He aims to dominate the wizarding world, oppressing those who are not pure - bloods and showing no mercy to those who oppose him.
One of the most iconic villains in fiction is Darth Vader from the Star Wars franchise. His imposing presence and complex character arc make him unforgettable.
I'd say it's Darth Vader from Star Wars. His fall from grace, his imposing presence, and his eventual redemption arc all contribute to making him one of the greatest villains in fiction. His dark side is legendary, but his internal conflict adds depth to his character.
In 'Star Trek: The Next Generation', the Borg collective has a manipulative relationship with other species. They assimilate individuals, forcibly integrating them into their collective, taking away their individuality and using their knowledge and abilities for the Borg's own expansionist goals.
In '1984' by George Orwell, the relationship between Winston and O'Brien is manipulative. O'Brien tortures and brainwashes Winston to conform to the Party's ideology.
In some fan fictions, Dumbledore is depicted as manipulative. This often stems from his actions in the original series that could be seen as him using Harry for a greater good. For example, he didn't fully disclose information to Harry, which in fanfic interpretations might be seen as manipulation.
If a villain enjoys inflicting pain and suffering on others without any remorse, they can be seen as extremely evil. Hannibal Lecter from 'The Silence of the Lambs' not only kills people but also eats them. He takes pleasure in the horror he causes, which is what makes him so terrifyingly evil.
Manipulative women can create conflict. In 'The Great Gatsby', Daisy Buchanan was somewhat manipulative. Her indecisiveness and her way of leading Gatsby on while being married to Tom created a lot of tension. Her actions led to Gatsby's downfall and ultimately the tragic end of the story.