Sam Witwer not only provides the voice and likeness of Starkiller, he also voices Emperor Palpatine, having earned the part during a read through of the script during development. See more
[Light Side Ending
You let me live. You tell me I'm a clone, but I chose to spare you. Maybe Kota is right. Maybe this is all a trick, a way to get me so confused that I'd forget who I really am and become your slave again. But either way, I let you live. I've finally broken your hold over me.
As long as she lives, I will always control you.