A Dreadnought is a towering armoured war machine that gives a grievously wounded warrior a second life as a walking engine of destruction. When one of the greatest Space Marines falls in battle, too broken to fight on yet too valued to be allowed to die, their shattered body may be interred within the sarcophagus at the heart of a Dreadnought. There, sustained by life-support systems, the ancient hero fights on for centuries more, their flesh fused with the machine they now command, its machine spirit bound to their own.
Standing far taller than a mortal man, a Dreadnought is armoured like a tank and armed with massive weapons: crushing power fists, thunderous guns, and other arms capable of felling monsters and cracking armour alike. It fights as both a revered relic and a living repository of memory, for the warrior within may have witnessed thousands of years of the chapter's history.
To be entombed in a Dreadnought is regarded as a solemn honour and a heavy burden. The occupant spends long ages in a death-like slumber between wars, roused only when their strength is truly needed, and the transition can be a torment to a soul that yearns for final rest. Yet in their waking hours these ancient warriors are near-unstoppable, striding into battle as the living embodiment of a chapter's endurance, wisdom, and wrath.