The Blacksmith can smelt ingots, as well as craft tools, weapons, and armor. Crafting items allows the Blacksmith to level up, which in turn can unlock new items as well as grant various bonuses. In order to begin crafting, one must first place a Blacksmith Anvil. Once placed, clicking on the anvil allows the player to open the crafting menu ("Show Workshop" icon, lower left corner). One can have multiple blacksmiths, though each require their own Blacksmith Anvil.
A Worker hearthling can be promoted to Blacksmith as long as the player has an available Blacksmith's Hammer. (to find out: How is availability determined? "Exists in inventory"?). The Blacksmith's Hammer is crafted by the Mason.
List of craftable items by category (incomplete) Edit