"Wilding" centers on Zena, a sixteen-year-old girl navigating a future version of New York City. Zena is an antihero, a term that gained popularity in the 1950s and 1960s. An antihero is typically a protagonist who lacks the conventional heroic attributes, often appearing graceless, inept, and at times, dishonest. Despite these traits, the protagonist may still accomplish heroic acts.

Zena exhibits several undesirable traits. She makes statements like "'Wilding' is a pure New York sport. No mushy woggers need apply," revealing her prejudiced views. She confuses being "coolish" with being smart, and much of the story's tension arises from her disdain for wisdom and her overestimation of her intelligence. For Zena, being coolish is crucial in her choice of friends: "There was something coolish, something even statue about [Nick]. And something dangerous, too, even outside the park, outside of wilding." She is drawn to Nick because of his cool demeanor and because he would irritate her mother. Conversely, Marnie's date is labeled a wogger, and despite his good looks, he lacks the cool factor Zena values. Her stubborn refusal to wear a collar that could transform her back into a human in case of danger borders on sheer foolishness.

Despite her flaws, Zena possesses some heroic traits and has qualities that make her relatable. She is acutely aware of her surroundings: "Soundless, [Zena] strode along by [Nick's] side, their shoulders almost—but not quite—touching. The small bit of air between them crackled with a hot intensity." This appreciation for nonverbal communication partly explains her enjoyment of wilding. She longs to feel the wind and, in her animal form, intends to read the scents carried by it. Her desire to become an animal temporarily reflects her wish to escape and experience life from a different perspective. This suggests she has an empathetic side and a yearning to understand other viewpoints, which might eventually help her overcome her arrogance and prejudice.

Zena possesses at least two notable heroic traits. One is her bravery, evident in her response to being attacked. Despite her instincts as a monkey urging her to flee, she chooses to fight back. The second trait is her ability to maintain her humanity even while in animal form, a feat most others cannot achieve. She observes, "At the foot of one tree was a body, human, but crumpled as if it were a pile of old clothes. Green face paint mixed with blood." Although the monkey part of her doesn't comprehend, the human part of Zena is present enough to question the scene, think of Marnie, and recognize that the presence of the body signifies something is amiss. "She sat by the side of the body," Yolen writes, "shivering uncontrollably, will-less." Yet, when confronted, she summons the will to revert to her human form and delivers a strong kick to the assailant. Her act of striking back against evil is a moment for which she can be greatly forgiven.

It is challenging to determine if she experiences any growth throughout the story. Carl Barkham, one of her rescuers, informs her that he and his fellow rescuers are part of the Max, a group tasked with guarding Central Park. Like Zena, members of the Max can transform into human form without relying on a protective collar or waiting for the radiation's effects to dissipate. Barkham mentions that Central Park is a daunting place, "And it's our job to make that fear safe. Control the chaos. Keep prime time clean." Zena's desire to join the Max is commendable, but it raises the question of whether her motivation is to help others or simply to be near Barkham, whose animal-like gait she finds incredibly appealing.