DHD Thaumaturgineering Service
DHD Thaumaturgineering Services was a firm consisting of a mixture of human, dwarf, and demon engineers, architects, mages, and craftsmen who were responsible for building many well-defending tombs, vaults, and other safeholds, active in the years 5137-5198. They combined their various skills and researched only human technology to build their crafts and became very famous as a result, often working for kings, queens or other high-ranking and wealthy noblemen and women, primarily in the Giusburg Outskirts region where their headquarters were centered.
DHD stands for Demon-Human-Dwarf, or often Dwarf-Human-Demon. Half of the plagues are written one way and the other half the other, depending on whether it was a demon or dwarf who made it as sort of friendly rivalry between the species. Human is always in the middle as its human members were happy to say "humans are the center of it all."
DHD Thaumaturgineering Service are responsible for the construction of the whiskey vault Vault Six-Nine-Six Alpha as well as the secret catacombs and vaults beneath the castle in Giusburg.
The firm shuttered in 5198 after years of decline and various accidents of misused / misunderstood magic and technology causing more harm than good. Its founders then tried very hard to erase its history and withdraw all its discoveries from the public eye, hoping to wait out the controversies after a few decades and have their children start it up again, but this never materialized, and the firm became more myth than fact.