So The Story Goes...
Hellboy was summoned from Hell by Nazi occultists and evil madman Grigori Rasputin to turn the tide of WWII against Allied Forces using the power of the nether world. Hellboy's true destiny is to bring about the apocalypse. That was until he was rescued by Professor Broom, founder of the clandestine B.P.R.D. (Bureau for Paranormal Research and Defense).
Professor Broom raised Hellboy as a son and protected him from the public eye. Hellboy grew up in the B.P.R.D. As he became an adult, his special powers made him a perfect candidate for a B.P.R.D agent. Hellboy now leads a team of freaks, including the mer-man Abe Sapien and the troubled pyro-kenetic Liz Sherman, in a secret war against forces of paranormal evil.
"I had always enjoyed reading folklore, legends, ghost stories, as well as monster comics and occult-detective stories. So I thought, 'What if I do a monster as a good guy who fights other monsters?' Hellboy pretty much fulfilled my life-long ambition to do nothing but draw monsters. Ten years later, I still love drawing it."
- Mike Mignola, Hellboy creator