Messinius’ Space Marines ran to the parapet edging the Penitent’s Square. On many worlds, the square would have been a plaza fit to adorn the centre of any great city. Not on Terra. On the immensity of the Lion’s Gate, it was nothing, one of hundreds of similarly huge spaces. The word ‘gate’ did not suit the scale of the cityscape. The Lion’s Gate’s bulk marched up into the sky, step by titanic step, until it rose far higher than the mountains it had supplanted. The gate had been built by the Emperor Himself, they said. Myths detailed the improbable supernatural feats required to raise it. They were lies, all of them, and belittled the true effort needed to build such an edifice. Though the Lion’s Gate was made to His design and by His command, the soaring monument had been constructed by mortals, with mortal hands and mortal tools. Messinius wished that had been remembered. For men to build this was far more impressive than any godly act of creation. If men could remember that, he believed, then perhaps they would remember their own strength.

The uncanny may not have built the gate, but it threatened to bring it down. Messinius looked over the rampart lip, down to the lower levels thousands of feet below and the spread of the Anterior Barbican.

Upon the stepped fortifications of the Lion’s Gate was armour of every colour and the blood of every loyal primarch. Dozens of regiments stood alongside them. Aircraft filled the sky. Guns boomed from every quarter. In the churning redness on the great roads, processional ways so huge they were akin to prairies cast in rockcrete, were flashes of gold where the Emperor’s Custodian Guard battled. The might of the Imperium was gathered there, in the palace where He dwelt.

There seemed moments on that day when it might not be enough.

The outer ramparts were carpeted in red bodies that writhed and heaved, obscuring the great statues adorning the defences and covering over the guns, an invasive cancer consuming reality. The enemy were legion. There were too many foes to defeat by plan and ruse. Only guns, and will, would see the day won, but the defenders were so pitifully few.

Messinius called a wordless halt, clenched fist raised, seeking the best place to deploy his mixed company, veterans all of the Terran Crusade. Gunships and fighters sped overhead, unleashing deadly light and streams of bombs into the packed daemonic masses. There were innumerable cannons crammed onto the gate, and they all fired, rippling the structure with false earthquakes. Soon the many ships and orbital defences of Terra would add their guns, targeting the very world they were meant to guard, but the attack had come so suddenly; as yet they had had no time to react.