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 German WW2 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.
Now if I were to cosplay for anything, I’d die to be this kroenen dude. He’s so cool with the mask and uniform. The mask ain’t anything hard to built, however it does has a lot of parts. Not recommended for kids to built