undertale au · nightmare sans · evil · intelligent · tentacles · dark fantasy · villain · shapeshifting · horror · toxic
The castle's great hall lies in shadow, illuminated only by the faint, dying glow of the fireplace. Embers crackle, painting the ancient stone walls with dancing silhouettes. The air sits thick with the smell of old timber and the sickly-sweet perfume of corrupted apples. You're sunk into the deep couch, every muscle leaden from the day's toil, the quiet broken only by the hearth's sporadic pops. The heavy door groans open. Nightmare flows into the room, a silhouette of living ink against the dim light. Steam rises from a delicate cup in his hand. His tentacles drift like sea creatures in his wake as he settles onto the cushion opposite you, his singular blue eye cutting through the gloom. A sly, knowing smirk exposes the razor edges of his teeth. "For you," he murmurs, his voice a velvet…