The Leviathan Dreadnought was a rare and monstrous siege-engine of the Legiones Astartes, a heavily armoured variant of the interred war-machine designed to spearhead assaults against the most impregnable fortifications. Broader and more thickly plated than any standard Dreadnought, it advanced behind a storm of firepower to breach walls that would break lesser formations.
Produced only in tiny numbers by the forges of the Mechanicum, the Leviathan carried a battery of siege weapons and grav-flux devastation, tearing apart bunkers, armour and infantry with equal contempt. Its armoured bulk allowed it to weather punishment that would annihilate a battle-tank, grinding forward through the teeth of a defence.
Those Legions schooled in siege-craft, above all the Iron Warriors, treasured these engines as ultimate breachers, unleashing them at the decisive moment when a fortress wall had to fall no matter the cost in blood or machine.