Warpsmiths are the dark reflection of the Space Marine Techmarine, Heretic Astartes who have forsaken the sterile doctrines of the Machine God for the heretical mysteries of the Dark Mechanicum. They are keepers of forbidden craft, exuding an unsettling blend of cold authority and barely-leashed madness. Where a loyal artificer coaxes cooperation from a machine's spirit, a Warpsmith dominates it outright, binding, torturing, and enslaving the ghosts within the metal to his will.
Their greatest and most terrible art is the making of Daemon Engines. Through corrupt ritual and forbidden alchemy, a Warpsmith drags a howling daemon out of the Immaterium and shackles it within a shell of iron and adamantium, forging living war-machines from the union of spirit and steel. Forgefiends, Maulerfiends, and greater horrors still answer to their makers as beasts to a cruel master, and it is the Warpsmith who keeps these unwilling servants bound, obedient, and ready for war.
Upon the battlefield a Warpsmith is a nightmare of writhing mechadendrites and coiling tentacles, able to seize an enemy tank and unmake it even as he stitches a wounded Daemon Engine back into murderous life. He tends the war-gear of his brethren, repairs the desecrated hulls of tanks, and turns captured Imperial machinery to the service of the gods. To the warriors of Chaos he is indispensable; to the machines he commands he is a tyrant wholly without mercy.