The File Restorer is a position assigned to a single supernatural being with the duties to restore corrupted elements of the world, known as "files", to their original condition.

Via unknown methods (though undoubtedly wicked), Morgrom the Essence of Evil was to ascend to this position in the mid-tenth century. Through abuse of his newfound authority, the Dungeon of Zork was not restored, but renovated to suit his wicked tastes. However, his reign was not permitted to last long. The Control Character deleted Morgrom from existance, thus passing the title to an unknown successor.

SOURCE(S): The Zork Chronicles