4. COUNT DOOKU

The dark side seduced this former Jedi and Darth Sidious made sure to manipulated him into it. He goes by the name Count Dooku, also known as Darth Tyranus.

“Powerful you have become, Dooku. The dark side I sense in you.”
“I’ve become more powerful than any Jedi. Even you.”
―Yoda and Dooku

Just as his master, Darth Sidious, Dooku masters the art of manipulation and the ways of the terror. He is a traitor and a murderer. He kills his old friend Sifo-Dyas so he can take over the army of clones, and he programs General Grievous, the cyborg, to follow his orders.

“General, the ongoing stalemate in the war has become unacceptable. There is concern you have lost your focus. Lord Sidious demands more dramatic results: more dead Jedi.”
“You expect victory over Jedi, but all you give me to fight them is battle droids. Bah!”
―Dooku (via hologram), speaking with Grievous