Samuel Witwer is a method actor.
Samuel Stewart `` Sam '' Witwer ( born October 20 , 1977 ) is an American actor and musician . He also voiced protagonist Galen Marek/Starkiller in the multimedia project Star Wars : The Force Unleashed , as well as The Son and Darth Maul in Cartoon Network 's Star Wars : The Clone Wars and Emperor Palpatine as well as Maul in Disney XD 's Star Wars Rebels .