Harry Domin is the thirty-eight-year-old corporate director of Rossum's Universal Robots. He is tall and clean-shaven, possessing a commanding presence at the factory. He views the robots as a means to free humanity from labor, hoping to create a worldwide aristocracy where humans only engage in leisure. His aggressive approach to business is matched by his direct, somewhat forceful courtship of visitors.

Helena is the elegant daughter of President Glory. She arrives at the factory representing the League of Humanity, intending to advocate for the robots' rights and improve their working conditions. She is initially naive about the realities of the factory and the directors' true intentions. Her deep empathy drives her to request unauthorized changes to the robots' programming.

Alquist serves as the chief of construction at the factory. He is older than his colleagues, characterized by his careless dress, grizzled hair, and untrimmed whiskers. Unlike the other directors, he maintains a deep religious faith and believes that manual labor is a fundamental, virtuous part of the human experience.

Radius is a robot who works at the factory but possesses a more developed personality due to experimental programming. Instead of standard robotic compliance, he exhibits defiance and a clear desire for independence. He actively rejects his status as a laborer and expresses a wish to rule over others.

Dr. Gall is a director at the factory who oversees the physiological and experimental departments. He works directly on the robots' programming, introducing physical sensations like pain to prevent workplace accidents. He is highly responsive to Helena's emotional appeals and willingly alters his scientific methods at her request.

Dr. Hallemeier is a factory director in charge of psychology and education for the robots. He enjoys leisure and luxury, firmly believing that the creation of robotic labor will allow humans to pursue a hedonistic lifestyle. He is immediately captivated by Helena's beauty when she arrives.

Fabry works as the technical director and chief engineer at Rossum's Universal Robots. He is focused on the mechanical and electrical infrastructure of the factory. Like his peers, he is eager to please Helena and fully supports the mass production of artificial workers.

Busman is the commercial director of the factory, responsible for the company's financial accounts. He is a pragmatic businessman who calculates the specific costs of clothing, food, and labor. He approaches the world primarily through the lens of economics and negotiation.

Robot Helena is a specialized machine created by Dr. Gall. She is designed to be physically beautiful rather than purely functional. Unlike standard factory workers, she is incapable of manual labor and possesses a more complex psychological makeup that mimics human traits.

Robot Primus is an advanced model machine working at the factory. Benefiting from experimental programming changes, he exhibits protective instincts and emotional capacities that separate him from standard, unfeeling labor robots.

Nana is Helena Glory's personal nurse. She is a deeply conservative and religious woman who views the creation of artificial life as an affront to God. She openly expresses her distrust and physical revulsion toward the factory's mechanical workers.

Sulla is a robotic secretary working for Harry Domin. She is highly capable, fluent in multiple languages, and possesses an appearance so remarkably lifelike that visitors frequently mistake her for a human employee.

Damon is an advanced robot model equipped with unique programming. He demonstrates strong leadership traits and a desire to govern, representing the upper limits of the factory's experimental design capabilities.

Old Rossum is the original inventor of the robots. He was a scientist who wanted to replicate human biology exactly, driven by a desire to wield the power of nature and effectively play God by creating artificial life.

Young Rossum is the pragmatic son of the original inventor. Recognizing that his father's attempts to create full human replicas were inefficient, he stripped the designs down to their bare essentials, removing emotion and soul to mass-produce perfect laborers.