Drones are the Overlord's workers: although they do not have enhanced senses or any defense, these workers who maintain and run the Meat Factory (and presumably other Overlord facilities) are super-strong; they lift Drum without strain. They are only found in Overlord installations, where there are invariably others nearby to defend them. A standard size of Drone groups is not mentioned in the book, although when Ella, Ninde, and Gold-Eye infiltrated the Meat Factory, they met a pair of them together.