Cain was (according to the Apocrypha) entrusted a knife by the Lord of Darkness with the ability to protect him from any harm and rule over those he wished. To unlock the Knife's power Cain would have to introduce murder to the world, which he did by dipping the blade in the blood of his brother.
Exiled from Eden by God for his crime, Cain took the Knife to Nod where he became ruler, and built an empire which lasted a hundred years before dying of old age. The Lord of Darkness declared that the knife's power would return every time the planets, moon and stars were alinged into the same position as when Abel was killed. Unlocked with innocent blood, the wielder could be given the blade's power for a century.
The Knife resurfaced in around 1000 BC when it fell into the hands of a descendent of Cain who used the blade to conquer a large empire and directed millions of slaves to build an underground city beneath modern-day Turkey. When the blade's power began to fade, and the man was no longer protected, he directed his people into the city where the civilization remained waiting on the power of the knife to return.
Three thousand years later in June, 1914, Indiana Jones and his friend Herman Mueller came across the underground kingdom and a plot by monarch Zed to use the Knife to rule the world. For their faith in the Lord of Darkness, no member of the city was innocent, so Jones and Mueller were taken captive for their blood.
In the boys' fight to escape, Jones and Mueller passed the Knife between each other until Zed finally snatched it back by the blade end and cut himself. The Knife stained itself black and Zed was suddenly engulfed within an invisible fire and died. The blade was stolen by Count Igor Ivanovich Stravsky and, in the chase which follow, he perished by falling down one of the city's corridors taking the Knife of Cain with him. Jones and Mueller blocked the entrance to prevent anyone from uncovering the blade.
The same day the blade touched Zed's blood, Franz Ferdinand of Austria-Hungary was assassinated in Sarajevo which led to the outbreak of World War I. Some believed the death marked the beginning of a century of killing.
- Young Indiana Jones and the Secret City (First appearance)