From what the info stated, the Rare Enchantment Scroll would upgrade any resource he had. For example, he could use it to upgrade the arrows, or the swords, or increase the durability of the gate or the walls. He could also use it to upgrade the catapult or ballistae as well.
But, he had another idea in his mind. And he would try it soon, about the 10th wave.
After checking the scroll, he returned to prepare for the next wave. Distributing the aether crystals to mages, replacing the arrows with the reinforced ones, and so on.
The five minutes passed in the blink of an eye, and the sixth wave arrived.
