“You know those lumithium pieces we find sometimes after burning the liches and Undying? If you can rip it out, it kills them. All their necrothralls, too.” Helena stared at him in surprise. “How’d you figure that out?” The only reliable method for permanently removing the Undying from combat was by burning them so hot and fast that they couldn’t regenerate, but when on fire, the Undying and the necrothralls would often plunge straight into the nearest cluster of combatants.
