Which was why Celestia was now making a personal visit to this realm of ash and dust. She took in a deep breath, the air dry, with the eerie, scratchy odorlessness of a world that was not dead since it had never truly lived. Tartarus was the name Equestrians called it, a term of which Celestia did not recall the origin. Not its true name, for that nopony knows, and none of the residents dare speak it. It was here, under ancient compact, that it was agreed that there be no permanent portal between Tartarus and the fragile world Equestria called home, except for the one gate and its one guardian of three. It was an agreement older than she was, and one she dared not trespass.