Mostly inspired by the Great Old Ones of H. P. Lovecraft’s Cthulhu Mythos with a dash of ancient Egyptian and Babylonian influences as well, the Ogdru Jahad are serpentine/crustacean entities which once resided on, and presided over, Earth. They are pitiless, chaotic, bent on destruction and subjugation and often so horrific in appearance that the mere sight of one of them sometimes induced madness.
The Ogdru Jahad are characters in Mike Mignola’s Hellboy comic. They are the Dragon of Revelation, and are destined to bring about the end of the world. Though the Ogdru Jahad are the ultimate antagonists in the series, they are not themselves active, their release from imprisonment instead being the object of many other villains’ plans. They were imprisoned in their Golden Cocoons by the Right Hand of Doom shortly after the creation of Earth, but not before they spawned 369 children, known as the Ogdru Hem.
After being imprisoned in the void, the Ogdru Jahad turned their considerable forces toward finding a way to escape their confinement and exact their revenge on the world. Since they are trapped in deep space, their contact with humanity is sparse at best. However, since the Ogdru Jahad are supremely powerful psychic entities, they have been able to establish contact with mortals on Earth in order to coerce them into doing their bidding.