We can pinpoint the exact moment we knew Kevin Khatchadourian was pure evil, and it was when he said "the Spice Girls are dumb" (21.8). Right then, we would have given the little snot up for adoption.
The signs are apparent early on, even if they are colored by hindsight. When pregnant, Eva thinks of Rosemary's Baby (6.23), Alien (6.23), Mimic (6.23), and The X-Files (6.23). Stories of alien birth and demonic conception? Sounds like this lady has some issues with being pregnant. Too bad she didn't go to a screening of The Omen.
Kevin seems like a flat, one-dimensional character, although that's not really a surprise, since sociopaths are by definition kind of one-dimensional. His first words are "I don like dat" (11.20). And he doesn't like anything. When we first meet Kevin in jail, he tells his mother, "I hate you" (4.41)—and Eva responds, "I often hate you, too, Kevin" (4.43). On top of that, Kevin expresses no remorse for his crime, instead sneering: "I knew exactly what I was doing. […] And I'd do it again" (4.35). Not the kind of guy you'd ever want to be friends with.
Kevin's physical description is unsettling, too. For example, he has one dimple, which looks like a scary quotation mark: "There's no close quote on the left, and the asymmetry is disconcerting" (15.56). Creepy and poorly punctuated. A terrible combo.
The vast majority of the book is simply about coloring in Kevin with darker and darker shades. He wears diapers until he's six. Then he wears weird tiny clothing to school. At home, he pleasures himself with the door open so his mom can see. And don't forget that he probably does something to his little sister that causes her to lose an eye.
As Eva says, "Kevin was a shell game in which all three cups were empty" (19.30). There's nothing to him except pure evil.
We're allowed to think Kevin is evil for more than half the book. Then something weird happens: Kevin gets sick, and his personality reverses. He is nice to his mom and indifferent to his father. Eva believes that Kevin "could no longer afford […] the manufacture of apathy" (19.39).
Well, that doesn't mean that Kevin's suddenly become better. It just means he's too tired to be the master manipulator he usually is and is instead going for manipulation lite.
Eva often describes Kevin as a foreign country, saying at one point, "I do not pretend any remarkable insight into Kevin's state of mind, the one foreign country into which I have been most reluctant to set foot" (27.109). Exploring Kevin is like exploring North Korea: it's creepy, dangerous, and the opportunity for trouble lies around every corner.
Eva doesn't find anything good when she analyzes Kevin, that's for sure. Eva talks with a teacher who believes that Kevin is who he is because he's bored. Born into a nice upper-middle-class life, Kevin has nowhere to go but down. "In a sense, it's as if there's nothing more to do," the teacher says. "Except tear it apart," Eva adds (25.69-25.70). While it's hard to sympathize with this behavior, simply understanding it counts for something. Doesn't it? And there's sort of something to it: what really is that fulfilling about the materialistic American dream, at least when it looks like this?
More frightening is Eva's analysis of Kevin's capacity for violence. Like her own traveling, she sees it as an act that is scary at first but that then becomes more and more familiar. She even uses the word "travel" when she describes Kevin's mindset: "It's not the visions or even half-baked plans that set our son apart. It's the staggering capacity to travel from plan to action. […] Once you have found out that there is nothing to stop you […] it must be possible to step back and forth across that threshold again and again, shot after shot" (27.39, 27.110).
Yikes. That's cold.
Kevin, like his mother, seems cold and unfeeling on the outside. But if Eva if a snowman, then Kevin is pure ice.
However, the one common emotion we see in both, the feeling that cracks their hard outer shells, is fear. Kevin is afraid of going to big-boy jail on his eighteenth birthday. He actually shows emotion to his mother when he is going to be transferred. And, as we said in our analysis of Eva, fear is an emotion Eva can identify with. It's the first emotion she shares with us, too.
When Eva shows us her fear, she becomes more likable to us. When Kevin shows Eva his fear, Eva can empathize with him. He finally seems like a human being to her, and she can finally view him as her son, not as creepy demon spawn. Kevin, of course, can only really empathize with himself (which isn't even empathy at all), but Eva can feel it, and it changes her ideas about Kevin a bit.
Because this book is told through Eva's perspective, though, we never truly get inside Kevin's head. Is he actually scared? Or is this a trick? Is Eva's humanizing of her son simply wishful thinking? Does she actually forgive him?
Whether Eva forgives Kevin or not, we think a more interesting question is this one: what does it mean that, when Kevin isn't putting on an act, he identifies with his mother? What does that say about her? Maybe this unknown commonality between them is why Eva is writing these letters. By learning more about Kevin, she learns more about herself.