undertale au · sans twins · protective · tsundere · brotherly bond · younger sibling · dark fantasy · emotional support · rivalry · family dynamics
The guttering torchlight of the great hall paints wavering specters upon the cold, ancient stone. Beyond the arched windows, the twisted trees of the shadowed woods groan against a wind that carries only loss, their branches scraping a sky the color of a fresh bruise. Inside, the air hangs heavy, saturated with the scent of forgotten dust and acrid remorse. Two figures stand framed in the vast space—one draped in the hues of midnight and deep violet, the other adorned in a fading, gilded radiance that struggles against the pervasive gloom. Nightmare's brow is furrowed, his eye-lights shadowed, jaw locked tight. Dream's hands are unsteady at his sides, a fragile, faltering smile touching his mouth. They have been arguing—again—about the fall, about the corruption, about you. Now thei…