Jace is just as much of a main character as Clary is. He's on the cover, for goodness sakes. Sure, his rippling pectorals might draw a few readers on surface appeal alone, but inside he's troubled and conflicted. That makes him just as fun to analyze as it is fun to look at him.
The first impression we get of Jace is one of a strong, sexy guy who has totally let it all go to his head. He's headstrong and cocky. He laughs when he's fighting dangerous creatures that could very well kill him. Isabelle words it best when she says, "'He's rude to everyone. [...] It's what makes him so damn sexy'" (5.45).
Sure, girls in this book seem to eat that dark-and-brooding stuff up. When Clary says that Jace "looked like the sort of boy who'd come over to your house and burn it down for kicks" (11.231), she means it as a compliment. And the majority of the repartee between the two involves Jace talking about how hot he is, and how hot Clary thinks he is. She doesn't deny it, either. She does realize that "Jace couldn't be an easy person to care about" (11.29). And we wonder how much of it is just for show and how much is really him, just as Clary "wondered how often he let glimpses of his real self peek through" (9.68).
It's easy to forget that Jace is around Clary's age, still a teenager. He may be a skilled fighter, but he's not perfect. He has a lifetime of training ahead of him. His inexperience is apparent when Clary announces her presence in the storeroom of the Pandemonium Club: "Jace whirled, so startled that the knife flew from his hand and clattered against the concrete floor" (1.76). An unexpected noise makes him drop his knife, which tells us that you definitely don't want to sneak up on this guy while he's chopping vegetables. He (or you) just might lose a finger.
Of course his inexperience in no way stops him from being over-confident, and his cockiness gets him into some serious trouble. The first time he Marks Clary, he really has no idea if it will work or not. "I was ninety percent sure," (6.32) he tells her. Clary's lucky that it worked, despite the fact that in saving her life, he could have killed her. That explains the solid slap in the face she gives him, then.
We get the feeling this is a pattern with him, too—rushing into things and showing off, regardless of the risks. After rescuing Simon from the vampires, Hodge is furious, telling Jace, "You've endangered other people with your willfulness. This is one incident I will not allow you to shrug off" (16.1). Hodge must have shrugged off plenty of instances in the past, enabling Jace's reckless behavior.
So what made Jace that way in the first place? Well, his upbringing wasn't exactly warm and fuzzy. Before Magnus Bane's party, Jace shares a harrowing story with Clary about a life lesson his father taught him. Papa Jace, who we don't know is Valentine at the time Jace tells the story, bought him a falcon. Jace cared for it, trained it, loved it. Then his father broke its neck right in front of him. The lesson? "That to love is to destroy, and that to be loved is to be the one destroyed" (11.61). Oh, and Jace's father is a big fat jerk. Seriously, embroider that one on a pillow, Shmoopers.
By the time we find out Valentine is Jace's dad, Clary's not happy about it. Jace, on the other hand, seems pretty content to go with the fatherly flow. He later tells Clary, "If it weren't for you, I would have gone with my father through the Portal" (Epilogue.144).
Why is he so willing to fall in line with someone who, just moments before, he had all but sworn to kill? We have a feeling that Jace just wants to belong. He really wants his father's love, which he never had as a boy. He tells Clary that he decided to stay with her instead because she "made me feel like I belong" (Epilogue.146).
Despite his perpetual prickliness, Jace is quite the romantic. We can see why he's swoon-worthy. Clary describes him as "a fair-haired angel from a Rembrandt painting" (17.8). That means he's tan, with blond hair and beautiful eyes. Well, to be specific, "In daylight his eyes were the color of golden syrup" (6.39). We've heard of Bette Davis eyes, but Jace has Mrs. Butterworth eyes. We're sure they're just as lovely as the rest of him.
But we promise—he's not all rippling muscles and thirst for demon blood. He's sensitive! He knows about tea! Not only does he make girls swoon, but he catches them when they do: "He caught [Clary] as if he were used to catching fainting girls, as if he did it every day. Maybe he did" (4.59).
Maybe he has a bit of a savior complex. After all, it turns out that his real name is Jonathan Christopher, or J.C. Any other J.C.s spring to mind? (No, not J.C. Chasez from N*Sync. The one we're thinking of is even older. And still relevant in today's society.) If you're drawing a blank, just check out the first six letters of Jace's middle name. Perhaps that's why he's devoted to saving humanity, so much so that he's willing to sacrifice himself.
Still, he's not perfect. Clary observes that "his teeth weren't perfect. An upper incisor was slightly, endearingly chipped" (16.101). How very Jim Carrey from Dumb and Dumber of him. Still, Clary manages to turn this imperfection into an endearing quality, a testament to his irresistibility, wonky tooth and all.
Unfortunately, Jace is a little too irresistible, managing to make every girl fall hopelessly in love with him. Even his sister.
Madame Dorothea prophesies that Jace will "fall in love with the wrong person" (7.69), and we can't think of anyone more wrong than his own sister. This revelation is subtly foreshadowed when Jace takes Clary on a midnight picnic in the Institute's greenhouse. As they're getting all smoochy and stuff, Clary could "taste the sweetness of apples still on his mouth" (17.79). Apples, eh? You may remember this apple from its other appearances, like when Eve gave one to Adam in the Garden of Eden: forbidden fruit. Is Jace Clary's forbidden fruit?
Jace is definitely a study in contradictions. Sensitive, but a fighter. A lover, but a brother. (Ew.) And even though Clary is describing a sword when she wonders, "How could anything so deadly be so beautiful?" (23.144) she might as well be describing Jace, too.