Domin: A handsome man of 35. Forceful, efficient and humorous at times.
Sulla: A pathetic figure. Young, pretty and attractive.
Marius: A young Robot, superior to the general run of his kind. Dressed in modern clothes.
Helena Glory: A vital, sympathetic, handsome girl of 21.
Dr. Gall: A tall, distinguished scientist of 50.
Mr. Fabry: A forceful, competent engineer of 40.
Hallemeier: An impressive man of 40. Bald head and beard.
Alquist: A stout, kindly old man of 60.
Nana: A tall, acidulous woman of 40.
Radius: A tall, forceful Robot.
Helena: A radiant young woman of 20.
Primus: A good-looking young Robot.
Note: All the Robots wear expressionless faces and move with absolute mechanical precision, with the exception of Sulla, Helena and Primus, who convey a touch of humanity.
