Right out of the gate, a few physical changes had to be made to Hellboy before he could make his big screen debut. In the comics, the character rocks a pair of blank yellow eyes, which is a tough sell visually. He also sported cloven hooves, which the filmmakers behind the 2004 adaptation realized early on would be difficult to pull off safely and convincingly. To add a layer of drama to the proceedings, he was kitted out with a new background, presented as a government secret — sort of a beefy, crimson member of the Men in Black. In the comics, he regularly interacted with the public, who weren't normally all that concerned with meeting a goliath from the depths of the underworld.
HB's origin story was also reconsidered. In the original "Hellboy" comic "Seed of Destruction," precious baby Anung Un Rama made his way to Earth through the sorcery of Gregori Rasputin, but his debut was a touch less dramatic. There was no firefight, for instance, and while there was a '40s era superhero present like in the 2019 Hellboy reboot, it wasn't the Lobster, but rather a Captain America-adjacent adventurer called Torch of Liberty. The Nazi forces behind the project were also miles away from where the bouncing bundle of demonic joy wound up materializing in front of his father figure, Professor Bruttenholm.
Speaking of, as wonderful a character as he was in the movies, played first by Kevin Trainor and John Hurt, then later by Ian McShane, the Professor's presence wasn't felt nearly as much in the comics. Hellboy's adoptive dad barely survived for a dozen pages in the comics before meeting his demise at the webbed hands of a terrible frog monster.
