Sacks was a 34 year old failed baseball player from Wabash, Indiana, who, with only a fifth-grade education, has been working as a lab assistant to Professor Gallaragas and his daughter, Helena, in making and testing the V.E.S. (Vril Energy Suit). While testing the suit, the lab was raided by assailants sent by Memnan Saa and Sacks was told by Helena into fleeing with the suit.
After hiding in a friend's apartment, Sacks came across the vigilante, Lobster Johnson, during a attack by a yeti that was dispatched by Saa and Axis agents. Sacks subsequently joined the Lobster and his companions on a mission to stop Memnan Saa. Together, the Lobster and Jim stormed Saa's hideout in the Lower West Side of New York City and Jim was able to subdue several Chutt warriors. However, Sacks stepped on a booby trap that caused him to fall through a trap door. He woke up in the frozen ruins of a temple and approached what appeared to be Memnan Saa before he was gassed and fell again into unconsciousness. While unconscious, Saa and his men took Anum's Fork from the back of the V.E.S. to use for their own purposes.
Jim woke up underneath a warehouse in Hoboken, New Jersey and found the brain of Professor Gallaragas floating in a jar and communicating with him. Gallaragas explained how Memnan Saa had tortured him and cut out his brain in order to learn how the professor was able to harness Vril energy. Gallaragas also explained the nature of Vril and how he created the device Anum's Fork to harness and channel the energy. However, before they could speak further Gallaragas' brain was shot by Memnan Saa, killing the professor. Saa then expressed surpirse to see Jim alive, as the gas that he inhaled earlier was poisonous. He then had one of his warriors attack Jim. This warrior had Anum's Fork attached to his back and over the course of the fight changed into a dragon-like creature and appeared to kill Jim, leaving him as a skeleton in the suit.
However, the spirit of Professor Gallaragas appeared to Jim. He explained to Jim that the Vril power was within him now, that Jim Sacks had become a "newly evolved superbeing." The Vril energy changed Jim, and because he was a good man he was rewarded and could now see "the universe and all her mysteries stripped away." The professor told Jim that he was a part of this mysterious new world and to move on, but before he did Jim got up one more time to use his new power to defeat Memnan Saa, kill his men, and make sure Saa would not be able to use the power of Vril.
The V.E.S. suit that was worn by Jim was destroyed in his final attack, the only piece left was his helmet which was taken by Nazi spies. The helmet was also destroyed after the Nazi submarine was blown up by Lobster Johnson.