Dr. Gustave Leech was a Nazi operative who was active during World War II. By the spring of 1942, he had relocated to the South American nation of Arbolivia where he operated a secret cell of spies and convinced a number of the locals to join the Nazi cause, including one Dolores Madrigo. They targeted American ships leaving port to deliver food and supplies to the people of England.
Their activities attracted the attention of Captain Terror, who traveled to Arbolivia to stop them. Capturing Dolores, Terror convinced her that she was fighting for the wrong side and got her to agree in assisting him. However, before she could tell Captain Terror of Gustave's next actions, she was captured by one of her former comrades. Taken to Leech, Dolores was placed inside a special torpedo of Leech's design: an air tight compartment where a human victim could be placed -- If they were not killed when the torpedo exploded, they would smother to death inside.
Leech attempted to launch this torpedo at the next American ship; however, it was stopped by an electromagnet device used by Captain Terror. With his submarine wrecked by Captain Terror, Leech ordered his vessel to surface and attempted to shoot the hero. Terror fought off Leech and then -- freeing Dolores from the torpedo -- hurled it at Leech's U-Boat. The torpedo exploded upon impact, killing Leech and his crew.
Leech was armed with two Panzers and torpedoes.
Leech commanded a Nazi U-Boat