Karl Ruprecht Kroenen is a fictional character in the Hellboy comic book series, created by Mike Mignola.
In the comics, Kroenen was a relatively unremarkable Nazi SS scientist, whose most distinguishing characteristic was that he always wore a gas mask and protective bodysuit, which Mignola attributes to a disfiguring accident of some kind.
Director Guillermo del Toro created a significantly expanded biography for the character, to appear as a villain in the 2004 film adaptation.
A German scientist working for the Nazi, and a member of the Thule Society, Dr. Kroenen became one of the top scientists for Project Ragna Rok, and a close disciple of Grigori Rasputin, along with Ilsa Haupstein and Leopold Kurtz. He was present with Rasputin at the secret ritual in Scotland that brought Hellboy to the world.
Read more about Kroenen at Wikipedia ...
Official Site: Mike Mignola
Links: Wikipedia Entry OAFE Kroenen toy/bio page Dark Horse Comics' Hellboy