The secret realm.
Grey didn't know how much time had passed, nor how many times he had tried to wipe out an army or hundreds of thousands. He had tried, failed, tried, failed, and tried again, and failed again so many times that he was almost starting to go numb about it. He couldn't leave, he had tried to leave after trying so many times without success, but he couldn't. There was no door in the room, and none of his attacks did anything to it.
He once again appeared in the scene, his body covered in dragon scales, his eyes giving off a bluish glow, he charged into the army, with a sword in his hand, he was a farmer harvesting his crops. With one slice, he cut through thousands of soldiers. Explosions were going off in different locations in the army of hundreds of thousands.