When we picture Doon, we imagine him having a serious but kinda dorky look about him (hey, who are we to talk?). He's usually thinking about something serious or focusing on some important task, as on Assignment Day when we get our first glimpse of him: "He sat with his shoulders hunched, his eyes squeezed shut in concentration, and his hands clasped tightly together. His hair looked rumpled, as if he hadn't combed it for a while" (1.6). Yep, that's a classic too-busy-being-nerdy-to-care-about-my-appearance look.
In fact, he's constantly characterized as serious, which is another clue that, well, he is. His eyebrows say it all: "He had dark, thick eyebrows, which made him look serious at the best of times and, when he was anxious or angry, came together to form a straight line across his forehead" (1.6).
But before you go thinking that Doon is all work and no play, we have to tell you that he's also a kind person who's motivated to help others. His outburst in class after being assigned the useless (in his opinion) job of messenger shows this: "The lights go out all the time now! And the shortages, there's shortages of everything! If no one does anything about it, something terrible is going to happen!" (1.50). Clearly, Doon wants to stop that "something terrible," unlike other characters we can think of (cough Mayor Cole cough).
For instance, when Poppy toddles off during the long blackout, Doon is the one to find her and take her inside his father's shop in order to keep her safe. When Lina tries to thank him, he acts like it's no big deal, saying "Anyone would have" and looking down at the ground (5.72). So yeah, maybe he's a little shy, too. Other characters draw our attention to Doon's kindness, too. Nammy Proggs (an old lady who lives in Doon's neighborhood), tells Lina, "He's a good-hearted boy. Anything breaks at my house, he fixes it" (5.76), Sounds like a keeper to Shmoop.
Doon is a majorly curious kiddo. He wants to know how and why stuff works. And luckily, his dad encourages him to investigate everything, which is pretty cool:
All Doon's life, his father had been saying to him, "You're a good boy and a smart boy. You'll do grand things someday. I know you will." But Doon hadn't done much that was grand so far. (3.39)
So it's no wonder then, that after Doon's first day down in the Pipeworks, his old man is dying to know how it went. He also asks specifically about the worm that Doon has been taking care of. That worm turns out to be a moth larvae that's about to go into its cocoon phase. Some people might think it's weird that Doon is so interested in insects, but his dad does nothing but encourage him.
When Doon reaches the Pipeworks, however, his curiosity about nature isn't exactly a-okay with his coworkers. Some of them notice him picking up various bugs, and they mock him, laughing: "It's bug-boy! […] He's collecting bugs for his lunch!" (8.4).
Sure, some folks may make fun of his offbeat interests, but Doon's inquisitive nature comes in handy more often than not. When he and Lina are exploring the parts of the Pipeworks related to the escape route, Doon is the one to strike the first match against its box and make fire. He thinks ahead and brings some matches back to the city with him, and when that last blackout hits, we're thinking that was a smart move.
As much as he likes technological stuff, like trying to figure out how electricity works, Doon is all about nature, too. When his worm finally transforms into a moth, Doon is amazed: "He knew he had seen something marvelous. What was the power that turned the worm into a moth? It was greater than any power the Builders had had, he was sure of that. The power that ran the city of Ember was feeble by comparison—and about to run out" (15.22).
The fact that Doon's so curious about the natural world helps him figure out the clues that get him, Lina, and Poppy out of Ember. In some ways, he's the perfect candidate to explore the aboveground world, since he can use his powers of observation to figure things out (like which foods are safe to eat). And he'll find plenty of interesting bugs to study in the new world, too.
Doon is far from perfect, though. If we had to pick his greatest flaws, they'd be pride and anger.
Doon's desire to achieve great things is motivated in part by pride and a desire for recognition: "He ached to do something truly important, like finding the source of electricity, and, as his father watched, be rewarded for his achievement. The size of the reward didn't matter. A small certificate would do, or maybe a badge to sew on his jacket" (3.39). We've got nothing against badges, but it seems like that shouldn't be the reason to do stuff, ya know?
Near the end of the book, when Lina and Doon are being sought by the guards, Doon convinces Lina that the two of them should leave Ember ASAP and oh so alone. Doon's reasoning goes back to what he feels he deserves for his achievements: "We can get away from the guards and leave our message behind us. And we can be the first ones to arrive in the new city! We should be the first, because we discovered the way!" (15.78). That sense of entitlement sounds the tiniest bit selfish, dude. But hey, we can understand that. Ember is not a place where it's easy to stand out.
Pride isn't the only driving force in Doon's life, though. He's also prone to fits of anger that are more than a little destructive. For example, when he gets home from his first day of labor in the Pipeworks, he stews about how "It was even more useless and boring than being a messenger. The thought made him suddenly furious. He sat up, grabbed a shoe heel out of the bucket at his feet, and hurled it with all his might. It arrived at the front door just as the door opened" (3.40).
The thing is, Doon's father is walking through the door right at that instant, and sure enough, Doon pegs his dad in the ear with the shoe heel. It was an accident, of course, but this is just one example of how Doon's anger can get out of hand. He'd better get a handle on that before he lands in even hotter water.
But hey, at least Doon knows what's up. When he finds himself feeling hotheaded, he knows it's not good: "He was angry at his anger, the way it surged up and took over." (8.6) It sounds like he's starting to take to heart his father's saying that letting anger have control of you leads to unintended consequences. And we sure don't want those, right?
Keep in mind, of course, that Doon's just a twelve-year-old boy. No doubt puberty is lurking around the corner, with all the hormonal craziness that entails. Still, we have to wonder what kinds of decisions Doon might've made differently if he'd been a little less angry and a little more fulfilled by his opportunities in Ember. Would he and Lina have told someone, anyone, about their plans to leave Ember? How much could that have changed the ending events in the book?