The heroes first learned of Serpent-Men first hand in the depths of Pteion. Inscribed in the labyrinthine tunnels were the chronicles of a distant past. Upon them, shapes humanoid but not human labored and created a vast civilization. They were seen bowing before the visage of a great snake, but yet a baleful star shone lonely in the sky. A portion of the walking snakes worshipped the star in secret. They brought its presence on the civilization and it crumbled, rotten from within and attacked from without.

A portion of the serpent-men shunned the star and sought refuge underground, taking the idols of the great snake with them. The rest stayed in the ruined lands, reveling insanely under the baleful star and wearing the faces of mortal men as masks. In the caves of the border mountains, the heroes later saw old, faded paintings, where many kings of old were serpent-men disguised as humans.

Barathus has later claimed that the Serpent-Men are the true driving force behind the Golden Masks. He claims they brough the Masks to west and intend to use them for their own purposes.