Ghal Maraz, the Skull-Splitter, was hammered from starmetal in the deep forges of the mountain-holds and given to Sigmar as a bond of kinship, forged in an age already lost to memory. When the old world drowned in fire and Chaos, Sigmar carried the weapon through the void upon the shattered core of a dying star, and with it he split the heavens open to lay claim to the Mortal Realms.
In the Age of Myth, Ghal Maraz shattered the horns of daemon-princes and toppled the god-beasts that had ruled the realms before mankind. No armour turns its head; no ward endures its fall. Yet when the Age of Chaos closed like a black tide, the hammer was lost, seized by the Everchosen and hidden in the Allpoints, and for long centuries the God-King mourned it as a father mourns a slain son.
It was reclaimed in blood by the Stormcast Eternals, who tore it from the enemy's grasp and bore it back to Azyr in triumph. Now it rests once more in Sigmar's hand, and where it is raised the free peoples of the Cities of Sigmar know that the God-King has not abandoned them. Each blow that falls is a covenant renewed: that Chaos shall not hold the realms unopposed while the Skull-Splitter still swings.