Lelouch and Nunnally
What can be said about these siblings. That they mean the world to one another.
Nunnally's strength comes from her brother. Her disabilities would have made most people resentful and vengeful. Nunnally however, is neither. She can stay at peace, her true and happy kind nature stays alive despite her hardships. Being with her brother is all she needs; she doesn't mind if she can't see or walk, as long as she's with Lelouch, she can be happy.
Lelouch's strength also comes from Nunnally. Nunnally is the reason he can still live, his reason to stay alive. Lelouch has nothing, he lost his position and his freedom, all he has left is his sister, and that's all he needs. He lives for her, to fight for her life and to protect her life, as well as her happiness.
Code Geass's whole plot revolves around Lelouch trying to do something for his sister. He wants to create the world where his sister can live peacefully, where she won't be afraid to open her eyes, and he doesn't care what it takes to do it. He will become a monster and even part with his sister, if she can have a world where she can live happily.
But that's the ironic thing. Lelouch only wants Nunnally to be happy, he wants to create a world where she can live in peace and happiness. But to create that world, he is distancing himself from Nunnally, he is becoming more of a terrorist, more of a murderer. He's too blind to see that all Nunnally wants is to be by his side, that she can live happily in a world of corruption, war and hatred if she can be with him.
