The Despairing Unfinished Building

If you find yourself thinking about going to a strange place, stop thinking about it immediately, or this despairing curse will come looking for you. "Mission failed. Commit suicide immediately." The red-eyed, expressionless man standing before me warned the "corpses" in the hall. Just moments ago, he had finally figured it out: coming back to life was no good thing. What could he have gone through to become a final warning in human form...