The Death Spire was a Sky Age human structure, built around the time of the Apparition of Humanity in what will later be known as the Desert of Death, as the 42 Sand Beings rose, to defend it from anybody attempting to trespass the grounds of the Death Spire. This structure was one of the Twelve Lost Cities of Mankind.
The existence of the Death Spire became a myth itself, and for long, people of Aiers wondered what was being guarded so jealously for such powerful creatures, that not even the great demon lords could face, and anybody who considered entering in the Desert of Death, was to suffer a horrible death. But despite of this, stories continued, about the great spire, standing alone in the middle of the desert.
After the War of the Lost Cities, and during the Third War of the Power, once humans had used the Holy Relic in all the other Lost Cities, the Sand Beings allowed the Holy Relic to enter into the banned grounds, and to activate the Spire: this will activate all of the Twelve Lost Cities at once, and trigger The Cataclysm.