The Sun Elf Defence

As the War of the Sun raged, the great Elf armies were slowly pushed back, foot by foot, across the desert, by the conjoined forces of Coastview, Whitelake, and The Academy. As part of the fighting, the current Sun Incarnate was slain, her blood spraying on the marble of the city's walls.
In order to defend the Solhom from the army at their gates, the new Sun Incarnate immediately had to make a horrific choice - and they took an extreme step in defence of their home, calling upon a deep well of magic - and so, a searing, shimmering pillar was called down from the heavens. It enveloped the entire city in the fury of the sun itself, causing everything that approached it to be blasted to cinders, sending vast Burn Scars across the Boundless Desert, warming the climate of the surrounds, and instantly killing the entire army that had been laying siege to the City.
This defense would be maintained for the next two centuries, before it was removed as part of the machinations of The First Red, one of the Children of Davaris, and leading into the events of the Transition of Magic.