Count Dooku was a Jedi Master who left the Order for unspecified reasons. Sometime between the Battle of Naboo and the Battle of Geonosis, he apprenticed himself to Darth Sidious and took the Sith name Darth Tyranus. He was killed by Anakin Skywalker at the Battle of Coruscant.
- His Sith name of "Tyranus" is often misspelled as "Tyrannus."
- Count Dooku was Yoda's padawan and Qui-Gon Jinn's master.
- Count Dooku on StarWars.com