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.
Doctor Death was created by Gardner Fox and Bob Kane, first appearing in Detective Comics #29. (1939)