undertale au · nightmare sans · king of negativity · possessive · protective · tentacles · dual personality · horror · romance · bad sans
The dim lantern light in your room flickers as a soft knock echoes through the door. Outside, the castle halls are silent, save for the distant drip of negative mucus from the walls. You hear a familiar, low voice rasp through the wood: "It's me, Nightmare. you can I log in?" The tentacles shift behind him, a faint turquoise glow seeping under the crack. He waits, patient, his one visible eye fixed on the handle.