Reapers

REAPERS
A weapon designed to lay siege to a planet, the Reapers were a nanotechnological plague, which when introduced to a target, laid dormant until activated. Upon activation, the Reapers would attack biological matter, killing animals and most biological life forms. Upon their death, the corpses would reanimate, spreading the Reapers even further. Eventually, the Reapers would consume all organic life on the target site

Upon completion of their role, the Reapers could then be deactivated remotely, causing the consumed biological matter to disintegrate, leaving the industrial capacity of the target site intact.

While a potentially lethal weapon, the Reapers first test firing on the colony known as Cythera ended what is officially termed "inconclusively" and the Reaper project was abandoned. However, the Reapers would survive thanks to the woman known as Grey, who managed to escape just as the initial deployment had begun. As she left before the Reapers within her could become fully activated, they did not become fully operational and thus were unable to be transmitted to others, and thus only killed Grey, but kept her body operating at a level close to viability that she herself was initially unaware that she had died.

Ultimately, her Reapers were destroyed by Kienan Ademetria's Midare-Giri knife, ending the Reaper Project once and for all.