The Kharadron Overlords and the Helsmiths of Hashut have a common lineage in the Khazalid empire of old – a culture that still endures relatively unchanged as the Khazalite Holds. The technology of their ancestors revolved around runes and the innate resonant magic of stone.
Both the Kharadron and the Helsmiths have since abandoned this technology. The Kharadron as there are not many rocks kicking about in the sky, and the Helsmiths as “harmony with nature” is not really how they roll.
Kharadron technology revolves around the use of a lighter-than-air material called Aether-gold, also called “the Breath of Grungni”. This powers not only their airships, but also their suits, weapons, and cities. In fact, without it, the entire Kharadron civilisation would quite literally come crashing to the ground. So the Kharadron dedicate much of their efforts to the finding and extraction of this valuable resource.
The Helsmiths have harnessed an altogether more dangerous material. Their technology runs on the distilled soul-essence of captured and processed daemons. As you might imagine, this is a volatile and unpredictable energy source, but incredibly powerful.
The Helsmiths believe that they are untainted by the use of this power, and that they have the willpower and fortitude to endure contact with this Chaotic essence. Their malevolent demeanor, sprouting tusks, and the fact that many of their most prolific magic users slowly petrify with use of this magical power source is entirely unrelated, probably.
This daemonic essence powers vast forges, which have become the greatest engines of industry in the Mortal Realms. These create vast arsenals of weapons and constructs for the Helsmiths and their dubious allies, taint the land about them, and drive the forced evacuation of other local denizens like skaven, orruks, and Gloomspite Gitz.
The forge in Arkanaut is a recently repurposed duardin hold that the Helsmiths have claimed and desecrated (as they see it, they’ve just retaken a piece of their ancestral heritage and put it to use again). There are some great shots of the forge in this episode, inspired by the custom scenery created to accompany the recent Helsmiths of Hashut battletome.
There is one more power source at play in this episode, of course.
In episode 1, the Arkanauts harpooned themselves a Stormcast soul and trapped it inside a jury-rigged aether-tank, intending to sell it back to its brethren at a fair and reasonable price (or possibly another party at a less reasonable price, depending on market conditions).