George Mulford was a ruthless career criminal who was active in the United States during the 1920s. He was arrested after a series of large hold-ups that he committed and was jailed. Breaking out of jail, Mulford stole an experimental spaceship to escape the authorities and soon found himself rocketed off to the planet Venus where he met a race of Venusians who welcomed him with open arms. While on Venus, he taught the people how to speak English and soon became enamored with the female named Vanza.
Learning how to use Venusian technology, Mulford freed a number of criminals from the "Water City" prison, promising them countless riches on Earth once he brought them to America. Forcing Vanza to accompany him and his minions, Mulford used his spaceship to return to Earth.
Arriving on the island of Barbuda during the early months of 1945, Mulford and his men used the advanced technology from Venus to slaughter the people of Barbuda and began ransacking the island's wealth. Their murderous attacks attracted the attention of the Sub-Mariner who happened to be vacationing in the area at the time. Namor's attempts to stop the Venusians always came too late, as he failed to stop them from robbing Barbuda's national bank, and kidnap Billy Steele, the British ambassador's son. Eventually, Namor rescued Vanza, who explained to him how they came to his world and led him to Mulford's secret hideout. There, Mulford's minions captured the pair and Mulford ordered their deaths.
Before his men could comply, the Sub-Mariner fought them off and then impaled Mulford on a stalagmite and then set his base to explode, killing all his men and the advanced Venusian technology.
Mulford wore a suit of Venusian battle armor.
Mulford had a number of Venusian weapons at his disposal: A gun that fired darts coated with a chemical that caused skin to burn, spears that released a gas that caused flesh to melt, bombs that made no sound when they exploded, and an electrified whip-like weapon that would coil around whoever it was thrown at.
Mulford had a space ship that could at least travel between planets as it had the ability to fly between Earth and Venus.