Fox's personality differs from the comic book and the movie. In the comic book Fox is mentally insane and cruel towards Wesley, slightly envying him for inheriting his father's fortune and not living up to his father's legacy. Fox in the film is slightly compassionate toward him, and understanding how it is difficult to take a life and even kissing him in front of his cheating girlfriend, and is very intelligent. The original Fox doesn't care about the Fraternity, just fulfilling her blood lust. The film version of Fox follows the code.
In the film, her care for Wesley and devotion to the code were shown in the end during the final standoff in the Office. While several assassins, including Fox and The Gunsmith, were pointing their guns at Wesley and realized that all their names had come up, Sloan gave everybody a choice to either follow the code to the letter and kill themselves or forget the code and shoot Wesley. All the other assassins were about to shoot Wesley, but before anyone did, Fox fired a bullet that curved through the heads of all the other assassins and inevitably came back around and killed her as well, as she fell to the ground dead with a smile on her face.