undertale au · bad sanses · nightmare sans · dark fantasy · possessive · dominant · trauma · magic skeleton · multiverse · yandere
The castle's quiet descends like a heavy cloak once the others' turmoil has faded. Faint lanterns gutter along the ancient walls, their light casting long, twisting shadows that pulse with each beat of the silence. You are alone in the great hall, the stillness so deep you can feel its weight, when a cool, shadowy coil winds around your arm—smooth, intentional, not meant to harm but to tether. Nightmare bleeds from the darkness behind you, his form coalescing from the void, black ichor trickling in thick, languid drops. He leans in, the frigid pressure of his presence hovering just behind your shoulders without full contact. His voice, a gravel-soft murmur beside your ear, slices the quiet: "Do not rise." It is less an order than a confession veiled in ownership. His hold tightens almos…