John has been through a lot, with his first mission on the asteroid belt in the Eridanus system and ending so far with the battle against the Didact. Summing up all the battles he has been in shows that he has been to war countless of times and always coming out on top, sometimes at the cost of a loved one. His most famous battles were of course against the Covenant, as depicted during the Halo trilogy, a number of books and the movies Halo: Legends and Halo 4: FUD.
My personal favourite battle of him was during Operation: FIRST STRIKE, where he really shows how good of a leader he is and how quick he thinks on his feet. I won’t go into further detail, but you should really read Halo: First Strike! But anyone who has really played the Halo games knows one fact, John, as far as the UNSC knows, is the only active SPARTAN-II left; this means that he loses his ‘equals’ and really suffers.
During one of the end cutscenes of Halo 4, John has a brief conversation with Lasky on the observation deck of the Infinity. Having just lost his last link to the SPARTANs, Cortana, in his mind he is now utterly alone. During that conversation, it became clear that this lonely soldier felt that soldiers and people were two different things -- and Lasky informed him that they were not. It is my believe (and we’ll only have to wait for this) that this simply line shook John to the core… Having been raised in such a weird and tough environment, he turned into the thing he was ‘designed’ for, more machine than human. He recalled what Cortana had asked him earlier, about who out of the duo was the real machine, and finally he found himself an answer: it was him.
If this has even half the impact I believe it had on him, it will make John rethink the route he wants to follow in the rest of his life. Will he be a machine soldier, or a human soldier? If the teaser trailer for Halo (Xbox One) is supposed to be more figurative than literal, he feels completely lost in the empty desert which his world suddenly became. He wants to show the world that he is more than a machine soldier and wants to show his humanity. The only way I think he can do that is to take his armour of, show the whole world his human side. But here is also a problem, how can John know what it takes to be human? He has never learned to really love someone, the closest he ever became to others were either his SPARTAN buddies or Cortana, neither had any real idea what it took to be human.
I suspect that John will now seek guidance from either Thomas Lasky or maybe even Catherine Halsey, the latter seems to me less likely, being imprisoned and all, but I wouldn’t mind seeing John and Halsey talk like humans. But what can John still do to ‘become’ human? I think this ‘becoming human’ thing is going to be the central theme for the upcoming Halo game(s) and will conclude at the end of the Reclaimer Saga. Seeing as I still think the Didact is alive, I would love to see John try to reason with him, the Didact is highly intelligent but was also a highly respected and high-ranking official. If John and the Didact could communicate, sit around the table if you will, the Didact would show himself more than a mindless brute.
So how would that go, a conversation between John and the Didact? The Didact hates all humans, since he thinks they are flawed and not worthy of the Mantle of Responsibility, while John would show him that humans are worthy and tries to convince him of this. During arguments threatens to destroy Earth with some kind of weapon and he flees, leaving John alone. Seeing how humanity is threatened, John will try to stop the Didact, but tries to do this without killing him. When John finally makes it to the Didact’s new weapon, he desperately tries to convince him not to kill them. The Didact does not listen and starts up his weapon, with the reticule precisely at Earth. John, still pleading goes to the Didact and throws himself before the weapon, being killed in the process. John’s major sacrifice shows the Didact that humans are more than the brutes he thought them to be.
So this is how I envision John’s story to end, sacrificing himself in order to save an entire planet, Earth. You probably have your own theory, please share this in the comments below!