Joe Grupper was a member of the Nazis active during World War II. By the winter of 1943, he was operating in the United States as a Fifth Columnist. He and his minions worked at Carroll Concentrates, a company that provided food concentrates to American soldiers during the war. Joe and his men laced the food with cyanide. They were given instructions by a Nazi spy located in Canada, who advised them where to ship the poisoned food through coded letters in the mail. The letters were so innocuous looking that they managed to slip past the American Censorship Bureau. When a shipment of poisoned food wiped out troops stationed on Caraway Island, leading to the Nazis taking over, it led the Human Torch and Toro to stumble upon the coded messages during a visit to the Censorship Bureau.
Paying a visit to Carroll Concentrates, the two flaming heroes caught Joe and his men in the act of poisoning a supply of concentrates headed for troops stationed in Iceland. The Torch and Toro were knocked out after Joe doused their flames with the showers of ice water used to cool boiling jello. However, the two heroes broke free and confronted Grupper, who, when faced by the heroes, swallowed one of the cyanide pills, preferring suicide over capture. With Grupper dead, the Torch and Toro stopped the train containing the poisoned food, saving the lives of countless soldiers.
Grupper had access to massive amounts of cyanide poison.