Character Analysis
Our protagonist, our narrator and our god-king of the universe. D-503 is kind of a microcosm of the greater society that created him. As such, he embodies their philosophy of complete submission to the State: of individuals proudly and happily serving as cogs in a giant machine. His status as the chief architect of the Integral means that the One State places a lot of confidence in him, and he responds by singing the praises of the State whenever he can.
The story basically covers his transition away from obedient automaton and into full-bore humanity. It's a frightening process, and one he's not sure he wants: he often refers to his emerging emotion in terms we normally associate with a contagious disease:
I continue to believe that I shall recover, that I may recover. I slept very well. No dreams or any other symptoms of disease. (12.1)
We can break it down into various distinct phases, and look at how those phases are reflected in his character.
A Happy Little Cog
When we first find D-, he lives a life of peace and bliss, much like the One State itself. Emotions exist for him, technically, but he doesn't quite know how to react to them:
As I write this: I feel my cheeks burn. I suppose this resembles what a woman experiences when she first hears a new pulse within her—the pulse of a tiny, unseeing, mini-being. (1.9)
He's much happier embracing his status as a cog in a machine, where everything works exactly the way it's supposed to:
I see myself as a part of an enormous, vigorous, united body; and what precise beauty! Not a single superfluous gesture or bow, or turn. (7.3)
His status here not only reflects that of the larger state, but also demonstrates his ignorance to the limits of his world. He doesn't see anything wrong with having no emotions, or functioning as a little piece of a big engine. It's peachy-keen for him. In the process, however, he demonstrates the limits that the One State imposes on human lives. We see no love or passion in him. We see nothing that he fears or hates, nothing that inspires him beyond the State itself. He doesn't see the limitations of his prison because he doesn't know anything else. Only as the story goes on, and those nice comfy wall come tumbling down, is he exposed to the rich variety that human experience is supposed to be. When does that happen? Funny you should ask…
I Don't Want to Feel These Feelings That I'm Enjoying So Much
In order for D- to grow and become more human, he has to suffer. A lot. In this case, the suffering is largely mental, as he is struck by these pesky little things called "emotions." The State can't stamp it out completely no matter how hard they try. In D's case, it arises from an age-old place: a member of the opposite sex. He hates her, of course, but he can't get her out of his head. And as his fascination grows, so does the conflict between what he thinks he should be (an obedient minion of the One State) and what he may become (an actual honest-to-gosh human being).
And inner conflict is definitely the name of the game with this guy. Almost from the moment he meets I-330, he's in a state of torment: trying to figure out desires and feelings that we think are natural, but he views as some kind of horrible affliction. He fights it, notably by referring to I-330 as an irrational number, and then stating "I had to find a way of eating up, of crushing down, that square root of minus one." (8.13) But appearances to the contrary, he is a human being, so the fight is a losing one in the end. Or a winning one, if you're interested in seeing him actually grow a soul.
Even so, it's a tough fight. Only in the end does he embrace his status as a human being, and even then he has his share of doubts. He refers to laughter as a "weapon," for instance ("you can kill anything with laughter, even murder," 35.31), and his emotional state often reeks of confusion and desperation.
But Wait, I DO have Emotions
As D- continues his journey, however, he eventually learns the value of emotions, and through them, learns to accept the uncertainty of life. He even uses them for good ends, such as getting O-90 out of the city where she can have her child in peace.
The book describes all of this as the emergence of a soul, which he actually goes to doctors to diagnose, but which he eventually cannot deny:
What formula could express this whirlwind that clears my soul of everything except her? Yes, my soul, yes … laugh if you want to. (27.6)
He's aware of how foolish his thoughts are in the context of the state, but he doesn't care. He learns that he can make a positive difference as an individual rather than as a cog in a machine, and he understands the value of that equation: a value completely divorced from the actions of the state.
Naturally, that's when the author yanks him right back into robot-hood when the State gets a hold of him (Russian authors tend to go for the grim stuff when they can). He reverts back to his former state of "purity," and cannot fathom why anyone would oppose them:
I hope we will win. More than that: I know we will win. Because reason should win. (40.9)
We can see what he's lost and the sad tragedy of the book is that all of his wanderings lead him back to the same state of mindless automation that he started at.
Even so, his actions may have helped bring down the State, and at the very least made a difference in a few people's lives. It's hard to spot with a guy whose name is a number, but all that really does add up to heroism.
D-503's Timeline