The Interrogator begins his narrative in a chillingly clinical manner, describing the torture session of a professor who had the misfortune to play K-pop songs to his class. In the Interrogator's mind, he and his crew are the "thinking, principled remainder of Division 42" (180). While the professor won't really fare any better after the Interrogator is done with him than he would have if the physically abusive Pubyok had dealt with him, he'll certainly have less visible scars.
Although he has no proper name, the Interrogator gets his kicks by writing biographies for each of his subjects. These biographies are important to him because they preserve for posterity (whoever that may be) the essence of the person lost through torture and death. In an ironic way, the Interrogator's all about identity—just not his own.
It bothers the Interrogator a little that he can't write his own life story, that he's supremely uncomfortable with using "I," even in his free time. It's clear that the Interrogator has given up his personal identity in service to the state. And even though he has parents who live with him, we curiously never learn much about who he was before he became a torturer.
In the end, when the Interrogator truly begins to have a problem with his lack of personal identity and network of people who love him, he even starts to doubt the story of his birth. He feels that his lonely life shouldn't be the product of the work he does; instead, it must somehow be the fault of parents who didn't love him as much as they could have:
... a notion had risen in my mind, the thought that maybe my parents had had a first family, that there were children before me that they lost and that I was a late, hollow replacement. That would account for their advanced ages and for the way that, when they looked at me, they seemed to see something that was lacking... (313)
As with Sun Moon and Jun Do, the Interrogator tells himself all manner of stories to account for his misery—but none of them are true. The fear in his parents' eyes and their lack of response to him as a family member have to do with the identity that he's stepped into as a torturer.
The Interrogator starts his narrative with a highly developed theory about torture and pain. He sees this stuff not for what it actually is—you know, the destruction of bodies and souls—but as something that gives a person the opportunity to leave behind a tainted identity for something new and clean. In this way, pain becomes cathartic rather than purely destructive. In the case of the professor, for example, the Interrogator thinks that pain offers the guy a chance at "rehabilitation" and life:
So we ramp up the pain to inconceivable levels, a shifting, muscular river of pain. Pain of this nature creates a rift in the identity—the person who makes it to the far shore will have little resemblance to the professor who now begins the crossing... There's no way around it: to get a new life, you've got to trade in your old one. (181)
Perhaps, like Jun Do, the Interrogator is just doing what he's told in order to survive. But it's clear that the Interrogator has firsthand awareness of what actually happens to the "subjects" who pass through his office: labor camps, lobotomies, dismemberment, death. He simply chooses not to see what's happening before his own eyes in order to make it through the working day. And let's not forget that if he were to acknowledge what was actually going on, he would have to change his entire worldview and question everything he knows about reality.
But all of this begins to change when the Interrogator encounters Impostor Ga. He's immediately fascinated by Ga's story because it includes love—something that is entirely mysterious to the Interrogator. On top of that, he knows that Ga is an impostor, and he really loves the idea that a person can just up and change his identity—and succeed in some measure.
He wonders to himself how Ga did it. How could a person change himself so much that he leaves prison and scores the love of a national treasure? It's an absolute mystery to him:
How had he pulled that off? And had love made him become someone else, or, as I suspected, had love suddenly appeared once he took on a new identity? I suspected that Ga was the same person on the inside but had a whole new exterior. I could respect that. But wouldn't the real change be, if a person was to go all the way, to get a new inner life? (276)
We can see the excitement building in the lonely Interrogator. Suddenly, the case of Sun Moon and Impostor Ga is no longer a job he's supposed to be working on: it's a self-help project. This revelation is the first step toward the Interrogator's final, radical scheme to meet the woman of his dreams.
The Interrogator may be an expert at creating "rifts in the identity" by means of the autopilot torture device, but the kind of pain required to shake the Interrogator out of his own emotional stupor is not actually the kind delivered by the autopilot.
The loss of his intern, Jujack, sends the Interrogator into an emotional meltdown that he didn't know he was capable of—and that he certainly doesn't understand: "And what was wrong with my memory? How come I couldn't recollect how I spent these painful days, and why was I okay with the fact that I couldn't recall them? I preferred it this way, didn't I? Compared to forgetting, did living really stand a chance?" (397).
We can see the Interrogator beginning to form his own identity precisely because of his experiences of relationships with real people. In this way, the Interrogator is building that new inner life that he so marveled at when he contemplated Imposter Ga's transformation. It's an ugly process, and he has a growing awareness that it's not going to lead to happiness, professional success, or love.
This process does, however, open his eyes somewhat to the truth around him: his society, the state that he has so relentlessly worked for, to the detriment of his soul, has betrayed him. His job's not about working for the communal good; it's about forcing people to obey the will of an oppressive state. In his anxious state, the Interrogator actually begins hallucinating this truth as he rides the metro:
I sat with the average citizens, and on all their bodies, I couldn't help but see "Property of" in raised pink letters. The mark was on everyone, only now could I finally see it. It was the ultimate perversion of the communist dream I'd been taught since childhood. (401)
He's learned the lesson Jun Do had learned before him: it's never enough to be the model citizen. The life story of the individual is always expendable in the hands of the regime. When the Interrogator decides to check out, it's with the hope that pain will give him a new inner life—or at least change him enough so that he no longer cares about the world around him.