Artifacts are powerful pieces of equipment that can be equipped for Lord-type units, granting them special perks. It was added to the game in patch 1.2 along with the Lords themselves.
There are five possible artifact slots currently in the game: Melee Weapon, Ranged Weapon, Magic Weapon, Armor and Magic Items. They can be found from monster camps, bought at merchants or found lying in the world. Higher level monster camps have a better chance of dropping powerful artifacts. Note that Sword of Black Swan is the only artifact which cannot be crafted.