The Quintessons, an alien race superior to any other, created Vector Sigma and a small planet about the size of Mars but much heavier and composed mostly of metal, which they called Cybertron . On this planet the Quintessons began a mass production of military and domestic robots, which they sold to other intelligent races of the Milky Way . One of the great buyers or loyal customers of the Quintessons were large humanoid-shaped aliens, which is why they created the robots in the likeness of these aliens.