Count Dooku - also known by his Sith name Darth Tyranus - is the supreme commander of the Confederacy of Independent Systems during the Clone Wars in the Star Wars series. He appears in Episode II: Attack Of The Clones and Episode III: Revenge Of The Sith portrayed by Christopher Lee. He also appears in the Clone Wars CGI TV series and 2D animated micro-series, voiced by Corey Burton.
A nobleman from the planet Serreno, Dooku was once a Jedi Master until his faith in the order was shaken following the terrible Battle of Galidraan. Leaving the order and reclaiming his birthright as a nobleman, Dooku would later turn to the dark side and become apprentice to Sith lord Darth Sidious. He used his great wealth and influence to persuade several Republic worlds to splinter from the Republic and form an alliance against the corrupt Galactic Senate. With the founding of the Confederacy, Dooku also reached out to many interplanetary corporate bodies to build vast droid armies to oppose the Republic. With the galaxy at war, Dooku and his master Lord Sidious would use the conflict as a means for the Sith to seize power and dominate the galaxy.
In Attack Of The Clones, Dooku had forged alliances with the Trade Federation and several other corporate and financial bodies. He also interrogated Obi-Wan Kenobi after he was captured inside the CIS droid foundries on Geonosis. Yoda and Mace Windu would later lead the Jedi and the newly-created Republic clone army against Dooku's droid forces, initiating the Battle of Geonosis and starting the Clone Wars. After duelling with Obi-Wan, Anakin Skywalker and even Yoda, Dooku made his retreat, but would resurface again leading the armies of the CIS into battle against the Republic.
Early on in Revenge Of The Sith, Count Dooku faces Anakin and Obi-Wan in lightsaber combat after they board the count's flagship to rescue the kidnapped Chancellor Palpatine (whom Dooku still did not know was his own master Darth Sidious). During the fight, Obi-Wan is knocked out and Anakin fights Dooku alone. Whether by Anakin's own lightsaber skills or some unseen Force intervention on Palpatine's part, Anakin gains the upper hand and defeats Dooku by carving off both of the count's arms. Holding both the count's and his own lightsaber, Anakin holds both blades at the defenseless Dooku's throat. Palpatine then urges Anakin to kill Dooku. At first Anakin is hesitant, but gives in to dark malice and uses both lightsabers to sever Dooku's head.