I like to believe that she gave Suzaku a Geass to enable him to pull off being Zero convincingly (Like, I dunno, it changes his voice or gives him extra gay movement or something) and that eventually she gave him her Code and then she got to die. And hence Suzaku lives as Zero forever... but. That's fanfiction-ish wishful thinking on my part, so... >_>

I dunno, I also kind of like the idea of her going on forever and ever, alone. I mean, she was in the background at the beginning and narrator (sort of) throughout season one... it's nice and melancholy to think of her as the observer from the sidelines who just sort of remembers everything... hm...