Dr. Herzog was a brilliant surgeon, who in 1935 contracted a strange illness that caused his face to become more and more deformed. Driven insane, he hid himself in a secret lab within his own home and began conducting grisly experiments while the world presumed him missing. Among his creations was his servant who had elongated arms and a massive dragon fish.
In the spring of 1945, Herzog's wife Mrs. Gaillard decided to throw a party at their mansion, and invited Betty Dean and her friend the Sub-Mariner to attend. That night, Herzog sent his servant out to capture his wife to be experimented on. However, her screams roused the Sub-Mariner who came to her rescue forcing the creature to flee before it could be seen. When Namor began searching the room, the creature grabbed him and dragged Namor to Herzog's lab. Herzog explained his situation and then revealed his intentions to distort Namor's body by increasing his mass. When the Sub-Mariner refused to be experimented on, Herzog then exposed Namor to a heat lamp sapping his strength and then tossed him into a pit. When Betty Dean went looking for Namor later, she too was captured and tossed in the pit.
When Namor' strength was revived by Betty's water bottle, Namor slew Herzog's assistant and saved Betty from the massive dragon fish. Herzog then attempted to kill Namor with a heat ray, but the hero turned it on Herzog. The scientist then set his lab to flood and set about sealing Namor and Betty inside. Namor managed to break them free, saving Betty from drowning. Chased by the Sub-Mariner, Herzog ran through a window on the top floor of the mansion and fell to his death.
Herzog was a brilliant and skilled surgeon. Later in his career he became an expert in body modification of both humans and animals. To date he used this skill to elongate his assistants arms and breed a dragon fish of monstrous size. He also apparently had the means to increase the mass of a human being, as well as extend an individuals legs.
Herzog was afflicted with a disease that caused disfigurement to his face; it also apparently drove him insane.
Herzog had a fully stocked operating theater to perform his grisly experiments.
Herzog had a heat lamp and heat ray.