Count Dooku is a fictional male Human in the Star Wars series. The character was portrayed on screen by Christopher Lee. His allegiance / loyalty is to The Sith. Count Dooku is the primary antagonist in star Wars II - Attack of the Clones. He is seen as the leader of the Separatists who are trying to break away from the Old Republic. Although he is a Sith Lord, he tries to warn and advise Obi-Wan Kenobi about the return of the Sith once Dooku has captured Obi-Wan on Geonosis. He manages to escape being captured by the Jedi Knights.
Count Dooku and General Grevious play key roles in the Clone Wars cartoon series which as they are set between the second and third films, their operations are canon.
In Star Wars III - Revenge of the Sith, he appears on General Grievous's battleship where he duels Anakin Skywalker and Obi-Wan Kenobi. When Obi-wan is knocked out, Anakin carries on the fight with Count Dooku. Count Dooku is eventually beheaded by Anakin after pressure from Palpatine.