Ullanor was once the seat of the largest Ork empire the galaxy had ever known, a sprawling greenskin domain whose warlord threatened whole swathes of human space during the Great Crusade of ancient legend. It was here that the Emperor of Mankind personally led the assault, breaking the Orks in a campaign so total that it became the stuff of Imperial scripture, and here that the great Triumph was held to honour the victory.
But Orks are never truly destroyed, only scattered like spores upon the wind. Across the long millennia the greenskins crept back to Ullanor, and what was once a monument to human supremacy festered anew into a teeming warworld. In time it swelled into the domain of a Beast so vast that it dwarfed even the empire the Emperor had shattered, and the Imperium was forced to wage a second, desperate war to stave off annihilation.
Ullanor stands as a grim lesson written across the ages: that no victory over the Orks is ever final, that the tide of the greenskin will always return to drown the works of Man. Whatever banners fly over its ruined plains, the earth itself seems to breed war, and the drums of the WAAAGH! echo forever across its blood-soaked continents.