The real reason we haven't seen Master Chief take off his helmet yet is because Bungie has been trolling us this entire time. Master Chief is just one, giant Troll Face underneath his MJOLNIR armor. How else do you explain this shout out in the recent, HD rebirth, Halo: Combat Evolved Anniversary? During the very beginning of the game, after Captain Keyes gives you the pistol for the first time, you'll be able to catch a glimpse of a tiny Troll Face on the bulletin board on your way out. In space, no one can hear you troll.