Let me add: I wonder what Lelouch would have done if Nunnally died and he was shipped off to Japan alone? In some ways, Nunnally was something he could fight for when everyone else had abandon him. She's not just his reason for starting the rebellion, but perhaps his reason for living. He's centered his life around her not because of any romantic feelings, but because she was something concrete that he could grasp onto and protect when the rest of his life was destroyed.
(no subject)