Random Trivia For This Title:
- Just like the first film, none of the cast member's names are written on the posters, mentioned in the trailers or shown in the opening credits.
- Christopher Lee was, reportedly, offered the role of King Balor, but had to turn down the role.
- Roy Dotrice (King Balor) and Ron Perlman (Hellboy) starred together in the TV series [Beauty and the Beast].
- As the Angel of Death, Doug Jones could only see out of the crack across the mask he wore. Also, the mechanical wings he was wearing weighed about 40 pounds. Doug was originally supposed to walk around the set, but when it was discovered that he could barely stand, they instead hung him from a wire. This is why The Angel of Death floats.
- Seth MacFarlane is actually fluent in German, having studied it for four years in high school and spent some time in Cologne, a fact that Guillermo del Toro was unaware of when he offered him the voice of Johann Krauss.
- David Hyde Pierce did the voice of Abe Sapien in the first film, while Doug Jones played the physical part. For Hellboy II, Jones also does the voice. The reason is because the producers hoped Pierce's name would make the first film a box-office smash. But he refused to be credited because he felt Abe Sapien was Jones' work, and as such did no promotions or interviews, or even attended the premiere.
- The start of photography was postponed by two months due to Anna Walton's pregnancy. She was eight months pregnant when auditioning for her role.
- The outline of the movie revolves a great deal around Ireland and Irish mythology: Nuada is the name of the first king of the mythological Tuatha De Danann people. The mythological Nuada bore the epithet "Silverhand" because, having lost his arm in battle, he wore a functioning silver arm. In the movie, Nuada's epithet is "Silverlance", and Nuada's father, Balor, has a mechanical arm.
- For the perspective shot of the elemental egg opening in Nuada's hand, a huge prosthetic hand holding an over-sized golden egg was created, and Luke Goss stood behind it.
- Guillermo del Toro wrote an ending which ultimately went unused: A secret base is found in the Antarctic, where Kroenen, the clockwork Nazi villain from the first film, is brought back to life as Rasputin steps out of the shadows. This would have been the setup for a potential third Hellboy film.