The exo-mantles were constructed by the Maltusian offshoot race known as the Controllers. These cousins of the Guardians of the Universe managed to construct an advanced battlesuit of armor for a peacekeeping force that would protect the territory of the Controllers. Thus, they formed NEMO which controlled the Darkstars; a police organization that served as a counterpart to the Green Lantern Corps. Similar to the Green Lantern Power Ring's, the exo-mantles were programmed with an instinctive hatred of Reach technology such as their Scarabs.