Nunn-Jahad was created alongside his six siblings by the great spirit Anum at the beginning of time, using some of God's powers. After the Seven Gods of Chaos awoke, they spawned the demonic Ogdru Hem into existence, who went to war with the spirits. The Hem were disposed by the Spriti's, the Seven Gods of Chaos were sealed in Gold crystal-cocoons and cast into the abyss. The only way to release them would be Anum's Right Hand of Doom.
He, alongside the six others, would influence individuals from afar, such as Grigori Rasputin.
Hell on Earth
Nunn-Jahad managed to escape from it's Crystal Prison during the Hell on Earth-story cycle of the B.P.R.D.-series.
Nunn-Jahad arrived in Argent, Kansas, where it started causing mayhem and spawned countless new Ogdru Hem. The forces of the B.P.R.D. and the SSS arrived and started to battle against the dragon and it's offspring.
Several factions tried to destroy the beast through both conventional and supernatural means, which included an nuclear strike as well as an attack by the Fallen Watchers from Hell, but all failed. Nunn-Jahad also attacked B.P.R.D.-headquarters, which resulted in death Katherine Corrigan and Panya.
The old one is finally defeated by Johann Krauss, who manages to channel the infinite power of Vril, killing both himself and Nunn-Jahad in the process.
Nunn-Jahad bears a resembles to an outdated depiction of the dinosaur-genus Ceratosaurus, notably possessing a horn on it's snout.
The body of Nunn-Jahad was also round, which could give the illusion of ineffective mobility, which still did not hinder the dragon's destructive capabilities.
Hellboy: Sword of Storms
Hellboy: Blood and Iron
Hellboy: The Golden Army