Personally, I think the Master Chief should have a not so heroic death, his mind has got to be totally -blam!- after all of the terrible things he's done and seen. Gravemind has picked at his mind, he has seen so many people he cares about die, he has experienced the flood, etc. I know Spartans are supposed to be mentally superior as well, but not being affected by all of the things that he has seen is just unimaginable. He sees hallucinations in Halo 3, so who's to say that he isn't still having hallucinations, and that they haven't gotten worse? I think that, in the last installment, that we should witness the Chiefs mental breakdown. We should see (through cut-scenes and in-game Occurrences) his mental state steadily going down hill (hallucinations, nightmares, things of that nature). In the very last mission there should be an event that finally triggers his breakdown. The very last scene of the game should show the Master Chief removing his helmet, thus finally seeing his face (which should have a look of finality upon it). There should be lots of radio traffic heard in the background trying the reach him. Finally the player sees him putting a magnum to his head, the screen fades to black and a shot is heard. Cue credits. TL;DR Chief goes crazy and commits suicide. [EDIT]: I just remembered Kurt adding his name to the MIA list shortly before his death, so I think that Chief should also do that before he removes his helmet. [Edited on 10.26.2012 9:17 PM PDT]