To most gamers and science-fiction aficionados, Spartan John-117, or more colloquially known as the Master Chief, is simply a generic space marine. For most of this character's life space, that has been the case. The most Chief has been known for has been the occasional one-liner. Perhaps the blame can be placed on Bungie Studios' desire to make Chief a blank slate players could project themselves on to immerse themselves in the role. Yet for those who have invested time and dedication to the books and other expanded universe content of Halo, Chief has always been Chief. With Halo 4, the Chief we had once known is dead.
343 Industries expressed desire to increase the scope and depth of the character throughout the months leading up to Halo 4's release. Yet it is apparent that at the same time, they wanted to differentiate their idea of Chief as opposed what Bungie had set down years before. This should not be seen as a insult to Bungie's work, but their games did indeed suffer from the cliches that plague the first person shooter genre and the biggest offender was Chief. Halo 4 took those cliches and played them straight at first before injecting a healthy dose realism into them. As much realism as can be expected from a science-fiction franchise, of course.
The game starts out with Chief waking up and fighting the Covenant again, this time without the motive to start activating the titular Halo rings that have for so long marked the Covenant's prime motivations within the games. Two books that led up to Halo 4, Halo: Glasslands and Thursday War by Karen Traviss, explain why this new sect of Covenant seemingly ignore the peace established at the end of Halo 3, but as with most players, Chief doesn't have this information to go on. He has gone back full-circle to face the religiously motivated foes he has always known.
Things begin to change when we meet the Didact, a member of the long-thought extinct a Forerunners, the architects of the Halos. This is revealed as the reason the Covenant have arrived at the shield world of Requiem. In prior Halos, the Chief is a big deal to both humans and the Covenant. He's THE Demon to the Covenant! He's THE Reclaimer to to Installation 04's Guilty Spark! He's THE hero to all of humanity. Yet what happens when he meets the Didact? He gets tossed away without a second though by the main antagonist of the game. Though he mocks the Chief in typical Saturday-morning nemesis fare, it is obvious that the Didact does not view the Chief as the great threat and/or hero he has long been established as being for so long. He is simply a pest to the Didact's long fermenting plans of retribution against humanity and the crimes he believes they are guilty of that date back hundreds of thousands of years in the past.
Perhaps one of the biggest shifts begins when the Chief meets the UNSC for the first time in 5 years according to the series timeline. While Commander Thomans Lasky, a character first introduced and expanded upon in the live-action series Halo 4: Forward Unto Dawn, is happy to see him and Spartan Commander Sarah Palmer gives him a playful nod, we soon meet Captain Andrew Del Rio of the UNSC Infinity. Del Rio's actions are definitely not something casual players would expect from a UNSC officer towards the Master Chief. Captain Keyes gave Chief the utmost respect in Halo: Combat Evolved and Admiral Lord Terrence Hood highlighted Chief's importance in Halo 3 by taking Chief's belief that Cortana was worth rescuing as the reason to join the Arbiter's fleet in attacking the Covenant Loyalists on the Ark. But Del Rio does none of that. He doesn't care for Chief's legend, he doesn't get wowed with a sense of awe, he treats him like any other solider and tries to put Chief in his place. Such a character would never be expected in a Bungie Halo game.
It is the hindrance of Captain Del Rio that ultimately begin to chip away at everything the Chief knows. Chief is a loyal soldier who feels that it is his duty to do whatever it takes to defend humanity no matter the cost. When Del Rio threatens to delete the further decaying Cortana as she slips into rampancy, Chief disobeys Del Rio's order for her dispensation for the first time in a Halo game and likely the first time within the expanded fiction. No longer is Chief the stoic super-solider who follows orders like a good little boy, he is breaking into new ground to complete his mission.
Another thing to consider is just how fragile the Chief turly is. Besides being tossed around by the Didact and not given the hero treatment he's come to expect, Chief isn't the invincible superman WE as Halo fans expect anymore. Before, Chief could just pop off a one-liner and get through most problems. Now, he has to speak up and he has to open up as a character, yet as a government-sponsored sociopath, he isn't very good at it. Like Cortana says before Chief leaves the UNSC Infinity to face the Didact alone while Del Rio leaves with his tail between his legs, who is the machine, him or her? His attempts to comfort Cortana when he doesn't even understand the impact of her rampancy is painful, not in a bad way, but a sad way. Chief is out of his element, something that hasn't happened since Halo 3 as he fought on without Cortana and Gravemind-induced "Cortana Moments" seemingly causing hallucinations in his psyche. Yet even that wasn't a huge problem for the Chief as he blasted his way though the Flood-infected High Charity to reclaim Cortana from the Gravemind's evil clutches.
Perhaps most shockingly of all, Halo 4 marks the first time Chief really loses and it has far reaching consequences. Chief is unable to stop the Didact from fleeing Requiem and obtaining the Composer, a device that digitizes organic life and at one time was the Forerunners last proposed solution to achieving immortality and a way to escape the terror of the Flood without firing the Halo rings. Yet such a device was used against the primitive, de-evolved ancestors of humanity by the Didact, driven insane by the Flood, to craft the Promethean Knights we face in Halo 4's campaign. History repeats itself as Chief is unable to defeat the Didact before he is able to Compose the Ivanoff research facility where the Composer was initially hidden and the Earth city of New Phoenix.
The ending further cements the blow of loss for the Chief. While he does stop the Didact, his victory comes at the cost of the life of his AI companion Cortana. Though their relationship was never long relatively speaking, the two were close. Because she was able to go into Chief's head and because of her programming, she was able to learn every facet of the Chief's personality, his fears, his hopes and who he is as a person. She essentially became a part of him and he was unable to save her. It was his job to protect her and he failed.
Now we no longer have the Chief that made famous phrases such as "I need a weapon". We have transferred to one who is, at his core, broken. And in the end, he is literally deconstructed piece by piece until his armor is peeled away and the Bungie-era taboo of not seeing Chief's face is lifted. Seeing into the eyes of this character leaves a feeling of dread and hope. Chief is empty and sullen, yet he is stubborn and not prone to giving up. Now that the character of Chief is free, he must learn to move on. He must learn what it means to be more than a solider, more than a soulless killing machine.
He must learn to be human.