The Hellsmith is the Chaos Space Marine-Version of the Techmarine. They have taken their talents and used them for their own ends. Amongst their creations are tainted weapons infused with warp power that the traitor legions wield. Hellsmiths are also infamous for creating the engines of war such as the Defiler or the Heldrake. They also build and maintain the weapons, armour, vehicles and structures for the Forces of Chaos.
In contrast to their weaker predecessors, the Heretics, the Hellsmiths have more health and are capable of defending themselves with a chain axe and a bolter, the bolter can be upgraded to a combi melta which is effective against vehicles. Like their loyalist counterparts, they can construct buildings faster than heretics. Hellsmiths are an HQ unit meaning you may only have one. Like heretics, Hellsmiths have forced labour which makes them work faster than usual. Their higher health, offensive capability and building speed makes them ideal for using to build structures at the frontline quickly. It's always a good idea to keep them protected so have some Cultists or Renegades to cover them. Do note that like Heretics, the Hellsmith can't be selected alongside other units.