Kroenen in the movie version is different from that in the comic. In the Hellboy movie, Kroenen is a ruthless and cunning assassin and is responsible for the deaths of countless people, including scores of Allied Troops, and Hellboy’s father figure, Trevor Bruttenholm.
As a teenager, he loathes his awkwardness and developed an extreme form of body dysmorphic disorder. He conducts a series of brutal experiments due to his surgical addiction, in which he surgically removes his own eyelids on both eyes, and both lips from his mouth. As a result, his face is horribly disfigured. He later designs a tight-fitting gas mask to filter out germs and protect his now-vulnerable face.