Ch-ch-ch-ch-changes. Yeah, it's easy for David Bowie, but not so much for Thomas. You might be wondering if Thomas's characterization has really changed from the Book Two, but, well, he's still pretty much the same.
For one thing, Teresa pinballs around in the kid's mind 24/7. Seriously, we just want to tell him, Thomas, dude, get over it. But as many of us may know, it can be tough to get over someone you once loved—especially when that person beats the crap out of you in a desert, only to tell you later that it was to save your life. Hey, we've all been there, right?
Even when Thomas is in a white room alone at the beginning of the book, he can't help but think about his ex-crush: "But most of all, he thought about Teresa. He couldn't get her out of his head, even though he hated her a little more with every passing moment" (1.16).
The change we see here is actually that Thomas is starting to hate Teresa more than he likes her. Same person, different emotions.
Wondering if our hero has become any more optimistic? Well, think again. Thomas seems to get more down in the dumps the more as WICKED manipulates—which is something that happens pretty much all the time. It's hard to blame him, but it wouldn't hurt for him to cheer up. When talking to Brenda in Denver, for example, here's what he says: "The only thing I've accomplished in life is to help set up an experiment that failed and tormented a bunch of kids" (28.40).
Um, okay, Mister Frowny-Face. Thomas never gives himself any credit for his accomplishments, and constant pessimism really does define him as a character. Sure, we still love Thomas, but boy, does he need to just shut up and pat himself on the back sometimes.
So, what else do we already know about Thomas? Oh, yeah: he's kind of dense. Remember, back in the Maze and in the Scorch, Thomas did some pretty ridiculous things. Like getting stung by a Griever on purpose. Or running towards every sound he hears to investigate. The kid just loves action—he just doesn't know how to keep his distance.
So, has Thomas grown any less dense in this third installment? Nah. Nothing seems to change. For example, when an infected person in a coffee shop starts to rebel against a government official, Thomas decides he wants front-row seats: "She was motioning frantically for him to get out. But Thomas wanted to watch what was happening" (30.3).
Pretty soon, Thomas is the only one in the coffee shop, and the government official figures out he's a Munie. Which then leads to Thomas being held hostage. Which then leads us to roll our eyes yet again.
Ah, Thomas, don't ever change. We love you and all your imperfections, which apparently are permanent.
This is the third book in the Maze Runner series, and WICKED has been manipulating and controlling Thomas ever since the very beginning of the first book. But Thomas knows that WICKED is doing this, and after all of the manipulation and hardships they put him through, something is bound to snap. And boy, oh boy, does Thomas snap: he turns into a monster.
And we're not just talking about the Frankenstein-ish "I can't let you do this!" monster that Thomas turns into when WICKED starts controlling his brain (27.27). We're talking about Thomas after he comes one of those cold-blooded killers with nothing to lose. Thomas has been exposed to death, torture, betrayal, extreme grief, dashed hopes—the list goes on and on.
So when you mix those things all together in a nice little bowl, you'll end up with a big glob of desensitized anger. In other words, you end up with a kid who's pretty angry but doesn't fear much anymore. Now, that's scary.
Right from the beginning, we can sense Thomas's newfound cold-bloodedness. When Janson tells him that they have good news, Thomas quickly snaps: "You didn't answer me. How can you possibly expect me to believe anything you say?" (2.20). In the Maze, Thomas may have jumped for joy when he heard there would be good news. But now, things are a bit different. He doesn't trust WICKED one bit, and he'll do anything to take them down.
Another way Thomas has become a monster is that he isn't afraid of killing anymore. Back in the Scorch, Thomas hesitated to stab and kill a Crank who was wayyyy past the Gone. For Thomas, it was hard to take a life, even if it was from a man who didn't have any control over his brain. But pain and frustration have truly taken a toll on our protagonist at this point: "He almost wanted to laugh at the irony. They had made him into a killer... to save people?" (65.10).
WICKED makes a lot of mistakes throughout the whole experiment with Thomas, but possibly their number-one mistake is that they turn Thomas into a killing machine. His anger is so intense that he even strangles Janson to death—and he doesn't seem too upset about it afterward.
Okay, so despite his new bloodlust and his resistance to changing his personality, Thomas does tend to take more control over situations in The Death Cure. In The Maze Runner, all we knew about Thomas was that he was special. In The Scorch Trials, he was branded "The Real Leader." But now, he actually takes charge without anyone saying You should lead. He just, you know, leads.
When trying to figure out who should stay with the Right Arm and who should go talk to their boss, Thomas decides he's making the decision, and that's final. He says to Minho: "You said once that I should be the Keeper of the Runners. Well, let me do it today" (47.11).
In other words, Thomas is basically saying, I'm taking control of this situation, so shut up. He doesn't need any sign in the street to tell him he's the leader; he doesn't need WICKED to fly a drone to Denver that says he's the Final Candidate. Thomas is going to lead because he simply knows how to, which is a much better way of leading than what he was doing back in the Scorch.
So what happened? What has made Thomas turn into this kind of leader? Maybe the change can be summed up by this thought, which appears late in the book: "He didn't care anymore. Whatever happened, happened. He knew that for the rest of his life he'd be haunted by what he'd seen" (56.9).
Thomas is a kid who's lost a whole lot, and his whole life as he knows it has been one giant manipulation. So he doesn't really care anymore what might happen. It's just going to happen, and that's it. He's already been traumatized enough by WICKED, so nothing he encounters in the future can make him feel any worse.
Yeah, that's how you get ahead in a YA dystopia. Deal with it.