Lui Ka was a desert witch approached by the fight Di Chen who sought a true challenge. Amused by his arrogance, the witch gave him his wish: he would fight the desert itself. Each grain of sand became a fierce warrior intent on Di Chen's death.
The battle would only end when Di Chen would admit that there were some challenges too difficult even for him. However it is said that Di Chen still fights to this day, showing that he has so far been able to do so.