The Krork were an ancient warrior-species engineered in the galaxy's distant past, and are believed to be the mighty ancestors of the modern Orks. Where their descendants are brutal and boisterous, the Krork of legend were something far greater: towering, disciplined super-soldiers created to fight in a war that would decide the fate of all life.
According to the oldest accounts, the Krork were bioengineered by the Old Ones as living weapons against the Necrons and their star-god masters during the War in Heaven. They were designed to be self-sufficient soldiers, hardy, endlessly reproducing, and bound together by an innate psychic field that made them stronger the more of them gathered in one place, a martial race that needed neither supply lines nor rest.
When the Old Ones fell and their creations were left to fend for themselves, the Krork endured as their makers intended: through sheer, unkillable persistence. Across the long ages since, they are thought to have degenerated into the Orks that plague the galaxy today, retaining their fungal resilience, their collective psychic power, and their bottomless hunger for battle, but losing the guiding purpose for which they were first made. In the Ork, the weapon outlived the war and forgot the reason it was forged.