The Threndakku Desert is one of the most inhospitable places in the fifteen continents, with blazing summers that last years and brief but violent monsoons where anything taller than knee-height is blasted by furious lightning. Here as with most places however, life persists, and silver-robed Threndakk tribes dwell in the deep wadis where shadow reigns.

Other creatures also live here, mainly underground, most famed among them are the crystal slugs who have a hide as impenetrable as iron, lubricated by strange iridescent oils. These huge slugs, longer than ten camels toe to tail. drill tunnels into the dry and dusty earth, feeding on the roots of plants and ancient trees, drinking from long-forgotten lakes buried beneath the dunes.

While hunting them is difficult, the tribes have managed it, for they have one attribute far more valuable than their sour tasting meat - towards the front they have a single perfectly spherical eye made of some sort of crystal, which grows over time like a pearl, enabling them to see beneath the soil, or so it is written.

Although nobody has yet been able to gaze beneath the earth by looking through these eyes, the Threndakks have found a novel use for them. By attaching them to tall and bending poles high above their warriors, they can focus fiery sunlight far more dangerous than the naked sun itself onto their enemies.

Caravans explode into flames, men wither like ants in a campfire, horses are charred to the bone, and no armour is proof against these wavering stalks of doom. The direction in which the light burns is controlled by thin strands pulled by tribesmen to either side, and they are typically arrayed behind the battle lines to reach forward and blind or destroy approaching enemies.