Although the first rudimentary designs did not survive, the idea did. Various incarnations of the killing machine with the spinning, stabbing and slashing blades began to assail the subterranean strongpoints of the Dwarfs. The first few Doom-flayers were largely Skaven-powered, as the pushing crew generated much of the impetus to spin the belts and cogs that drove the whirling weaponry. The Skaven crew, protected by a scrap-barrier of old shields, metal-reinforced planks, and even the patched-together armour plates of fallen enemies, could just about avoid incoming missile fire and steer the device to plow into enemy lines.[1a]