Mercenary Camel Riders

Though horses are a good enough mount for traversing the desert, they are not necessarily designed for it. Camels, on the other hand, are born and raised in the desert and are perfectly adapted for travelling across the dunes. They store water on their backs, can handle the heat better, and have more long-distance endurance than horses. In a way, they are a fundamental and pivotal component of living in the Dead Sands. Travellers often hire or rent camels when visiting and many citizens of the desert own their own camels in case they need to travel across the sand (at least, if they can afford it). 
This trend of popularity also applies to the Carrion Kings’ armies. Mercenaries that have lived or worked in the Dead Sands for an extended period of time will likely have experience in riding and handling camels. These soldiers are sometimes grouped together and fielded into dedicated camel rider divisions. These units act as supplements to regular supply lines but also, in battle, act as powerful shock cavalry. Though not as innately fast as a horse, camels are better suited for traversing sandy terrain and are surprisingly sturdy. Apart from the largest and heaviest troops, Camel Riders make for surprisingly good shock cavalry when deployed effectively - chasing down and breaking light infantry, ranged units, artillery crews, and other such enemies.