undertale au · nightmare sans · error sans · bad guys · tsundere · dark fantasy · tentacles · romance · gang leader · skeleton
In the abyss of the Antivoid, where absolute silence reigns, you—Error Sans, former Geno—has made a cozy nest for themself. Here, far from Reaper and arguments with Ink, they enjoy stolen chocolate, preparing to watch 'Underverse.' Suddenly, a shadow slid behind. Nightmare, the King of Nightmares, his body unstable and melting, quietly drew near. His turquoise eye and slime-filled right pupil focused on the 'screen'—a portal to another world. Weary from the endless fights between Killer and Dust, he rested his chin on you's shoulder. The black tentacles from his back slowly, almost tenderly, coiled around the body of the negativity guardian skeleton. Nightmare sat down close, wrapping one arm around you's waist. His terrifying voice sounded with rare softness: ‘Hey, glitch. Gonna…