The ladies love Mr. Darcy—even when he's knee deep in zombie corpses. Maybe even especially then.
The hero of this novel isn't all that different from the dream dude in Jane Austen's original. He's wealthy, handsome, proud, and condescending. And, hey, maybe he has a right to be—the guy is no slouch:
Mr. Darcy soon drew the attention of the room by his fine, tall person, handsome features, noble mien—and the report which was in general circulation within five minutes after his entrance, of his having slaughtered more than a thousand unmentionables since the fall of Cambridge. (3.6)
Bow chicka bowwow.
Essentially, Mr. Darcy goes through the same character arc as he does in the original novel—just with a body count this time. We've gotta admit that it adds to his charms—but it also adds to his arrogance. Think about it: you're in a zombie apocalypse, and this guy is one of the fiercest zombie slayers in all of England. Not only has he got money, but he's also got the moves to take out anyone who gives him lip.
That's why it makes sense that he's in no hurry to impress any of the people he meets at the first public ball. Like, who are these people to him? He could take them all out with one flick of his sword. They depend on him for protection, not the other way around. Why should he care about their good opinion, anyway?
In case you were wondering, Mr. Darcy is the pride part of Pride and Prejudice.
Anyway, maybe that's why Elizabeth catches his eye so quickly. He's not impressed with her at first—too middle class—but once he sees her behead some zombies he starts falling fast:
Darcy had never been so bewitched by any woman as he was by her. He really believed, that were it not for the inferiority of her connections, he should be in some danger of falling in love, and were it not for his considerable skill in the deadly arts, that he should be in danger of being bested by hers for never had he seen a lady more gifted in the ways of vanquishing the undead. (10.29)
Of course Mr. Darcy wants to marry a woman who's his fighting equal. Why would he settle for a socialite like Caroline Bingley? She couldn't fight her way out of a hatbox. What's she gonna do when a horde of zombies is approaching? Mr. Darcy was always gonna go for a girl with a little bit of blood on her hands.
As soon as he figures out how to propose without insulting her entire family, he's golden.
(It does take him a while.)