Marvin Simmons was the father of Thomas and Christian Simmons. He was an employee of A.S. Industries, co-creator of the Bio-Suit and personal aquaintence of Alvin Severnya and Dr. Hugo Schneider.

Simmons worked on the Bio-Suit project as the engineer. He was kept in the dark about the suit's real purpose as a weapon and when he found out he stole the blueprints and the suit to prevent Severnya and Schneider from finishing it. He disappeared shortly afterwards, much to the dismay of Severnya who considered the Bio-Suit his property.