The most famous of the criminals to adopt the name Doctor Death is Karl Hellfern, a mad scientist and supervillain who fights against the Batman in Gotham City. His plots usually revolve around lethal chemicals and biological weapons, as he is a brilliant and completely amoral chemist. He has been a member of the Science Squad on Oolong Island.
The New 52 reboots Doctor Death as a scientist who developed a bone-growth serum that turned him into a disfigured monster. However, both versions of him are still one of the first super villains Batman has fought.