Gold Tempest. Stormspire, #4

The world is running out of magic-and the war to claim what remains has begun. The secret of the Engine is no longer hidden. The great clans know the truth: power is finite, and only those who seize it will survive the collapse. To secure their future, the Ashen Pyre and Skycrest Clans have united in a brutal campaign to conquer the continent. Standing in their way is Kal Stoneveil-no longer a student, no longer a weapon, but a general.
Tasked with holding the strategic fortress of Thunder-Gap, Kal must do the impossible: train an army from shattered survivors, command a war fought on an unprecedented scale, and force his way toward the forbidden Gold Tier-a realm of power where cultivators shape the land itself. Walls rise from glaciers. Firestorms are drawn from volcanoes. The battlefield becomes a living weapon. But every step toward ascension strips away something human.
As Titan-class enemies capable of leveling mountains enter the field and betrayal spreads through the ranks, Kal must decide what he is willing to burn to win. Because the fortress will fall. The war will not stop. And when the storm breaks, the world will remember who stood at its center. Gold Tempest is an epic progression fantasy of siege warfare, mass combat, and the terrible cost of command-where victory is measured not in glory, but in what survives the storm.