agents, like Sanakan, Dhomochevsky, and Iko who may derive from core personalities uploaded into the Netsphere. Exterminators - A subset of Safeguard which is made up of black-and-white-colored, silicon-based, bio-mechanical, humanoid robots. These often use primitive, close-range weapons as a means of attack, but because of their formidable armor, it is not much of a problem. They come in different classes of power, though the hierarchy is never explained. The lowest, most common safeguard attacks with just its hands. A higher type attacks with larger, clawed hands, another with large shear-like weapons. The 'Class One Exterminator', encountered near the end of the series, eschews melee attacks for esoteric weaponry and the capacity to transform the City's structure itself. Safeguard Exterminators seem to run on a different protocol of command than the higher level of Safeguard such as Sanakan and/or Dhomochevsky (though Dhomo did have a contingent of them assigned to him before Schiff destroyed them). At one point, the Exterminator Class One even targets Sanakan as it deems her a threat or obstacle, but does not decide to kill her. It is up to speculation as to why - perhaps either it no longer saw her as a threat, or perhaps it was because she too was a Safeguard. Governing Agency or Authority (originally ), - The ruling level of the Net Sphere. It tries at times to assist Killy and Cibo against the Cyborgs and against the Safeguard. It has powers identical to the Safeguard, but cannot directly control the Safeguard - although it can hinder them. It wants a human with the Net Terminal Gene to be found to stop the Builders which are the cause of the runaway growth of The City. Builders (originally , meaning Architect) - Machines which construct The City. They are not connected directly to The Net Sphere or Safeguard; therefore a human with net terminal genes is only capable of their activation. They come in a wide variety of shapes and sizes. Killy remembers their language in the village of the Fishermen, and Cibo uses her knowledge about them to learn to control them completely. A group of builders in the higher megastructures of The City have been modified, possibly by long deceased humans, to behave socially, conversing with the beings they encounter and taking moderately humanoid appearances. Structures The Megastructure (originally ) - These are large plates that lie between levels