Knull born in darkness, was an ancient malevolent deity whose existence predates the universe itself, and was originally content to drift through the endless abyss that existed before time began. Bruce Banner theorized that Knull was merely an aspect of the One Below All, or a creature it somehow controls.

When the Celestials began creating the universe, Knull was awakened by the "Light of the Creation" and outraged by his kingdom of darkness being despoiled. Knull retaliated by creating a sword of living darkness, the All-Black, from his newly-cast shadow, decapitating one of them. Cast back into the void by the other Celestials, Knull used the slain Celestial's severed head as a forge to temper his sword in its cosmic energies. Intent on devouring the divine light that had usurped his kingdom of darkness, Knull manifested a symbiotic suit of armor from the eldritch darkness he commanded and embarked on a genocidal campaign against the other gods,[9] becoming a legendary figure of terror for divine beings even billions of years later.