(SPOILER ALERT FOR THE NEXT TWO GAMES) EDIT: Cortana is defiantly not dead because... Cortana represents Master Chiefs mind/spirit. Without her he is hollow, that is why he is quite in the last scenes, he is empty. The next two games will be about his quest to regain his mind/spirit by trying to regain Cortana. He will be tested not physically, but mentally/spiritually and find that he can go on without Cortana (whether that is from him or another AI I can't say). But by the end of Halo 6 Master Chief will have learned how to live without Cortana (one way or another) and he will either get Cortana back or be the one to finally killer her. **My only speculation** Cortana will be the villain (or on the villain side) in one or both of the next games. [Edited on 11.09.2012 12:38 AM PST]