The Craftsmen are a society responsible for the design and construction of all official buildings in Arindell. They also built the tombs used by Slayer Dragons up to the mid Fifth Age and all the regalia worn by Slayer Dragons, as well as their weapons and armor.
The story of the craftsmen began with Eieber's Long March, before the Slayer Dragons even became a thing. According to legend, a detachment of soldiers under Eieber's command rescued the villagers of a small settlement in Ataya. Among them was a blacksmith married to a tailor, and when they were brought before Eieber, the smith swore to make him such a suit of armor that he would never see harm. The story holds that all craftsmen are descended from this couple and their children.
Galactis offers what he feels is a more accurate account in the Accepted Histories: the craftsmen were likely drawn from many different nations throughout the Long March and served in Eieber's army repairing equipment. Because his army had to essentially live in the field on the move, Eieber and his men relied heavily on their artisans to keep their weapons and armor in good condition. As such, the craftsmen were much sought-after and highly revered.
When the Long March ended, these tradesmen were set to work designing and building Eieber's new capitol city: an important task, as the city was set to endure for centuries. At this point, the craftsmen were mostly skilled in creating and repairing combat equipment, so artisans of every kind were brought in from all over the new Alliance and joined the ranks. The craftsmen needed someplace to live while the city was being built, so they set up camp in the valley at the site of their modern city.
They make stuff; or rather, they make everything: weapons, armor, clothes, locks, keys, treasure-chests, tombs, decorations, utensils, gardening-tools, you name it. The only things they don't make, are edible; and they make the best (on Arindell) of everything else. Skills are usually passed in families; but not always, and this varies from Age to Age.
The Craftsmen's devotion to the Order of Slayer Dragons has been compared unfavorably to religious fanaticism. Though officially citizens of the Alliance, the Craftsmen profess loyalty only to the Slayer Dragons. Their city is isolated from the rest of Arindell and they frequently refuse to follow city ordinances set by the Alliance. They are, in truth, answerable only to the Slayer Dragons.
Craftsmen of Dragon Descent
The Craftsmen's city is in a side valley connected to Stormreaver, on the slopes of High Mountain. Normally they would not have been allowed to build there, but Draco made special arrangments. This proximity, and the generally more welcoming nature of the Craftsmen's village made their dragons more comfortable visiting them in human-form. Many relationships started, and by the Sixth Age it was estimated that 3 out of every 5 craftsmen had at least some dragon blood.
Through the Long Night, while the Craftsmen were living underground, they relied heavily on the High Mountain Flight for support, interbreeding with them even more. By the Age of the New Day, every craftsmen was at least partially dragon.