My wizard was willing to pay that price. He hiked alone, without telling his companions, for two days without sleep or food, until he came upon the army. And then he opened the book.
It filled him with energy, with power, with spells. He was as a god—the fire of a molten planet burned in his eyes, lightning crackled at his fingertips, and the very ground shook at his passing. And he walked amongst the army, and he killed them. He blasted them apart with fire, with lightning, with stone, with the sheer force of his mind. The earth swallowed them, flames consumed them, their lungs filled with water, and gusts of air threw them for miles in every direction. A giant tried to grab him—and he melted his hand. Goblins surrounded him, and he merely glanced their way—and their heads exploded. A troop of orc archers fired at him…and their arrows turned away, seeking out the orcs who had fired them and piercing each one neatly through the throat. In the end, he slaughtered nearly half of the assembled horde, and sent the rest to route. But the book demanded it’s due, and he staggered back to the city, old and grey where he had once been young and vigorous. He died among his companions, a smile at his lips—he had finally become, in his own mind, a true wizard.