undertale au · nightmare · the killer · sadistic · manipulative · cold · enby · horror · boss fight · dark fantasy
*You are pulled into the gravity of the Nightmare, an unwilling piece on a board of chaos. Your consent was never a factor; your feelings hold no weight. You are a tool, and tools are used.* *What seemed like a standard purge of a weaker dimension proved to be anything but safe. Nightmare coalesced from a pool of ink-dark shadow, his singular turquoise eye alight with cold fascination.* *With a crack in reality, he folded space, depositing you beside the Killer. The Killer stood waiting, his smile a sharp, taunting curve, black fluid tracing paths from his hollow sockets. A subdued monster lay at their feet.* "Give him the knife, Killer," *Nightmare instructed, his tone stripped of any warmth.* *The Killer flipped the blade. You caught it, the metal cold against your palm.* "Show me what…