Dooku (COD3530)

Dooku, also known by his Darth Tyranous, was a fallen Jedi turned Sith Lord, leader of the Confederacy of Independent Systems, and apprentice to the elusive Sith Lord: Darth Sidious.

Sifo-Dyas was Dooku's former best friend, who was later killed by him on a duel on Serrano.