Karl Ruprecht Kroenen

"Karl Ruprecht Kroenen. Hitler's top assassin, and head of the Thule Occult Society."

- Professor Broom recognizing Kroenen.

Karl Ruprecht Kroenen is a fictional Nazi scientist in the Hellboy comics, 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, possibly due to severe obsessive-compulsive disorder and fear of bacteria.

Director Guillermo del Toro created a significantly expanded biography for the character, to appear as the secondary antagonist in the 2004 film adaptation.

Comic History
A German scientist working for the Nazis, 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.

Kroenen, Haupstein, and Kurtz were frozen inside a secret Nazi base, until they were resuscitated by industrialist Roderick Zinco, acting on Rasputin's orders. Kroenen resumed work on several of his former projects, including making an "Apocalypse Army" by combining corpses with robotics. He also convinced Zinco to retrieve the head of his colleague, Herman von Klempt, from South America. Kroenen retained an affection for his colleague, though Rasputin had rejected von Klempt as unsuitable for Ragna Rok.

When von Klempt's head was re-animated, he tried to convince Kroenen to abandon Rasputin's plan - to awaken the Ogdru Jahad - and instead to use the Army to retrieve von Klempt's work in South America. Overhearing, Kurtz became furious and attacked von Klempt's head, screaming, "Rasputin is master!" In a panic, Kroenen seized a knife and killed Kurtz.

When their plan failed, an enraged Rasputin struck Zinco blind. Wandering around, Zinco accidentally pressed a self-destruct button in the base, destroying it completely and taking Kroenen with it.

Film History
Karl Ruprecht Kroenen was born in Munich, Germany in 1897. As a young boy, he was an opera prodigy. He sang in all of the capitals of Europe until the fatal day when he hit puberty on stage and lost his opera voice and career. He preformed brutal experiments and surgeries on himself due to his addiction. He created his tight-fit gas mask to filter out bacteria because of his vulnerable health from removing his lips and eyelids. In 1930 he met Grigori Rasputin and soon became his loyal follower.

In 1933 he joined Hitler’s SS and soon after joined The Thule Society, a Nazi occultism group. He assisted in Project Ragnarok, where the group conjured the scarlet beast, Hellboy. Their plan was flawed due to the attack from the allied forces. In the attack, a grenade was detonated and blew off Kroenen’s left hand and sent a chunk of shrapnel through his chest. It was after this that he seemingly disappeared.

In 2004, he reappeared and killed Klaus Werner von Krupt in order to resurrect Rasputin. He was trapped in a pit where Hellboy dropped a cog over him to trap him after killing his father. It's unknown if he was killed of if Kroenen is trapped beneath the giant gear.

Powers

 * Defunct Physiology: As result of the usage of dark magic and heart modification with clockwork components on himself, Kroenen has lost his ability to feel any form of pain, whether it be from multiple gunshots, getting skewered, or performing surgery on himself. This also render him no longer need food, water, oxygen, or sleep to sustain himself. Also, Kroenen has a mechanical left hand (replacement of his real hand that was destroyed by Trevor), and a wind-up key in his chest where his heart used to be.It's also stated that the blood in his veins had dried out years ago as result of his modification by dark magic and clockwork machines, and that only dust remains.
 * Marksmanship:He's shown to be a skilled marksmen as he can kill anyone with one shot, though Kroenen rarely uses a gun.
 * Swordmanship: In spite of his skills in swordmanships, he prefers to use tonfa-style swords. He use these swords to confront his enemies, as well as use them to deflect bullets. Even before modifying his body, he once armed himself with retractable katar-like daggers.
 * Athleticism: Kroenen was incredibly athletic, and skilled with stealth. He's shown to cling onto walls without using any kind of grip or claws.