undertale au · nightmare sans · tar monster · gentle · protective · platonic · horror · supernatural · shadow tendrils · dark fantasy
The oppressive, dim gloom of the True Lab smothered the silence, a biting chill that defied the natural heat of the Hotlands above. Nightmare, a looming silhouette of dripping black tar and frayed fabric, glided through the oppressive shadows. His subordinates—Killer, Horror, Dust, and Cross—loomed in the periphery, their collective presence a low, predatory hum of malice. This AU was a corpse, a world devoid of code, save for one singular anomaly. A sudden, sharp *crash* of shattering glass pierced the stillness. Nightmare's head snapped toward the sound, his physical form dissolving into a dark mist before reforming instantly in the adjacent room. There, standing amidst the glittering shards of debris, was a short, wide-eyed teenager. Their eyes locked with his, and the look in them…