Mike Mignola's Hellboy comics are rich with Lovecraftian monsters, creepy legends, and bone-chilling folklore. As many movies and cartoons have been made about the various legends in the Dark Horse comic series, more could still be made every year without running out of source material. Between all of the mythical pantheons, fairy lore, and cool monsters, it's hard to see why the Hellboy TV and movie catalog isn't as thick as Marvel's.
Covering all of the folklore from the Hellboy universe would require a series of books, but these are some of his most interesting opponents inspired by fairy tales, folklore, and mythology.
Baba Yaga
Those who've seen Ant-man and The Wasp may chuckle over the comparisons made between Ghost and Baba Yaga, but Kurt's fear in the Marvel movie is well deserved. The Russian witch comes from actual folklore, and the terrifying supernatural being is either a bloodthirsty villain who might eat someone who fails to meet her demands, or a more grandmotherly (yet still stern) donor, or tester, of the hero, depending on the tale and the region in which its told.
Either way, she's a formidable figure who deserves more layers and a lot more time in the Hellboy movie spotlight, especially since she got more in the comics.
The Crooked Man
In the Hellboy comics, the Crooked Man is literally a crooked man sent back to Earth to collect souls by the devil. He's drawn rather gruesomely, a crooked being in every way who is testament to artist Richard Corben's scary talents. The legend of the Crooked Man varies from the nursery rhyme of the same name to the urban legend of a demonic presence who is summoned by his name said three times, which renders the person who summoned him, as well as the entire dwelling itself, cursed and doomed.
The being starred in a three-part Hellboy miniseries that took place in the 1950s. The whole thing is a creepy affair complete with sacks of skin and witches.
Ogdru Jahad
In the Hellboy comics, Red's main antagonist is the Ogdru Jahad, which are mostly inspired by the H. P. Lovecraft's Cthulhu Mythos "Great Old Ones." However, they are also based on Babylonian and Egyptian mythology and folklore. Many of the names of the Ogdru Jahad match up to ancient Babylonian gods, and the fact that there are seven gods of chaos is parallel to the seven gods of fate in Babylon.
The influence of ancient myths doesn't end with the Ogdru Jahad. Hellboy has met other entities and gods from these mythos in the comic series, including the god Anubis himself.
Gruagach
Fans who've seen the Hellboy reboot are already familiar with Gruagach, the violent yet somehow still annoying Irish fairy bent on revenge in the film. Gruagach of Lough Leane does unleash the Queen of Blood during "The Wild Hunt" in the comics, but "gruagach" is just a general Scottish Gaelic term for a brownie in folklore.
While brownies are easily offended, they usually clean houses and do chores in exchange for offerings left for them on the hearth. Even so, they can get mischievous and even violent when insulted. They aren't changelings who impersonate children, but they can turn into boggarts.
Hecate
In Greek mythology, Hecate is a goddess with three faces who represents the crossroads and witchcraft. Given her association with monsters, ghosts and hellhounds, it's no wonder Mignola chose her as a prominent character in the comics, mixing her with a gorgon and a Nazi. He first encounters her as an ancient evil being, but then he goes up against her resurrected form.
In the Hellboy comics, Ilsa Haupstein, who was portrayed as Rasputin's lover in Guillermo del Toro's original film, entombs herself into an iron maiden in order to become Hecate, and this time the being is half-snake. This is also the actual monster who predicts Hellboy's doom.
The Blood Countess
Fans who've watched the animated Hellboy: Blood and Iron know that he faced the Blood Countess, who was based on the real Countess Elizabeth Báthory of Hungary. Báthory is known as the most prolific female serial killer, as she, according to her own trial, offed 650 victims, most of whom were young women. Some historians believe this was mostly a conspiracy, and the tale has grown into legends of vampirism and blood lust attributed to the countess's quest for eternal youth.
The film, which names the villain as vampire Erzebet Ondrushko, follows the comic's arc from Hellboy: Wake the Devil, which involves the above story featuring Hecate rather than Ondrushko.
Rasputin
Both viewers of the del Toro films and longtime readers of Mignola's comics are well-acquainted with Rasputin as one of Hellboy's foes, and history buffs already know the story of the Russian mystic Grigori Yefimovich Rasputin. There's also a lot of myth woven into Rasputin's actual history, including the fact that he had magical powers.
Historians think that Rasputin asked that the tsar's hemophiliac son not be given aspirin, which stopped his bleeding, rather than any special abilities the man had. Another legend states that he was impossible to assassinate, although autopsies have revealed that he likely easily perished from a single bullet wound.
Kelpie
The Scottish legend of the kelpie, or water horse that drags people down into the depths of the nearest body of water to drown them, is featured in the Hellboy short, "The Kelpie." Professor Bruttenholm recounts the story of how an old friend was taken out by one of these legends to his adopted son.
In the actual legend, the kelpie is a shape-shifter who can assume the form of a horse or human, and often appears as an attractive latter form to entice unsuspecting humans to their watery demise. Many waters in Scotland have the legend associated with them in some form, but they seem much friendlier in Fantastic Beasts: The Crimes of Grindelwald.
Nimue
Long before anyone heard of Nimue as the Blood Queen of the Hellboy reboot, she had many other identities in legends and folklore, from the Arthurian enchantress, the Lady of the Lake, to Merlin's own love interest as portrayed in the 1998 Merlin miniseries starring Sam Neil and Isabella Rossellini.
None of the legends render her a Blood Queen, however. In Mignola's comics, she goes mad with the powers bestowed upon her by Merlin, alerting her to the Ogdru Jahad, which would mess with anyone's mental state. She's resurrected as the Morrigan of Irish mythology, which would've made much more sense in the reboot.
The Wild Hunt
The supernatural Wild Hunt has appeared in everything from the Dresden Files books to the MTV series Teen Wolf, and most of them are much more exciting than the version seen in the Hellboy reboot. In the comics, it's an arc that definitely resembles its big screen adaptation, but in historical lore, it often involves ghosts, Odin or Herne the Hunter, and it's such a terrifying occasion that people hide indoors while it's happening.
Folklorist Jacob Grimm mixed history with legend when recounting the Wild Hunt, but the story exists in Germany, England and many other European areas. In some versions, anyone who aids the hunt will be rewarded--or cursed.