For reasons unknown, at some point approximately 2,000 years ago, the Engineers stationed on LV-223 initiated a plan to wipe out humanity by releasing the potent mutagen Chemical A0-3959X.91 – 15 they had created. This Engineer was among those who participated in the plan. However, they apparently lost control of the pathogen which led the Engineers there to die off. The Engineer, along with three of his brethren took refuge within their ship and stored themselves within their ship's Sarcophagi, likely to wait for the pathogen to die off. The Engineer's brethren weren't so lucky, as their chambers ceased to function, causing them to die, while his continued to function.