The Regal Tombs of Orbis were the place where the richest of the rich were buried, and Bert was sure that if he could break in to a recent two-month old burial he would be wealthy for at least the rest of the year. Since tomb-robbing could get somebody the gibbet, he had gone alone, and now he cursed as he fought hand to hand with the bulbous, distended, decomposing corpse that had leapt up when he tried to steal the grave goods and now beat and clawed at him and swiped at him with a rapier. Every wound it inflicted on his body, he got a little weaker and to his horror, it grew a little stronger and a little less rotten. Not long afterwards, a seemingly living man left the tomb, leaving the body of a grave robber behind. A body that would soon rise...and walk...
The desert is a curse from the Water God upon the wicked people who live in the South.
Said people offended the Water God in some way, and so the Water God placed water-trappers, bizarre, water-sucking beings, in the soil, and within years, the wilderness became a desert.
Thus, the desert folk shamans have special powers that allow them to find water-trappers so that they can be dug up and their water harvested.