Rahothep, the tomb king
In the centre of the desert in the south of the world you can find the pyramids and tombs of the old civilisation from Arabia, better known in our days as the land of the undead. This name describes the situation exactly because you wouldn't find any living creature there. From the largest pyramid, the so called "black pyramid", Rahothep reign over his terrible undead army. To execute his will he has his armies of mummies.
More than two thousand years in the past the kings reign over a large country. The powerful kings were embalmed and buried in pyramids as a preparation for their glorious life after their dead. The most powerful king was Rahothep and he was buried in the "black pyramid".
Nearly thousand years later a human sorcerer uses the powerful magic spell "Great awaken" but he fails. Due to this spell Rahothep and his army was awaken long before the time has come. Because of their awaken to early they were half decay. The plan was a failure but Rahothep still believe in his dream from a golden age. His powerful armies break out of the sand to subjugate the whole world.