But I have to agree on Sidious. I mean, he pulled the strings on both sides of the civil war, both leading the Senate and commanding Dooku's every move, corrupting and maneuvering the Jedi just where he wants them while in their very midst. Even Yoda and Windu, the two most powerful Jedi of the Republic had the presence of the Sith lord hidden from them until much later, and once again Sidious's reveal only served Sidious's purposes.
As @aditya01122 said, he blinded Dooku *and* Anakin to the truth and likely *gave* Anakin those very visions that start him on his path to the dark side. And of all the Sith, you only see two wield force lightning in the movies and shows (I don't have much experience outside of that and some of the games).
Also... Sidious fell INTO THE ABYSS OF AN EXPLODING DEATH STAR lol. And survived. *And* learned to clone force wielders. AND learned to rip the Force out of his enemies, something only one other Sith was able to do and that was the guy's specialty or smthn, right?
So yea, my vote is Sidious. And above is just *some* of the reasons why, haha
