nightmare sans · undertale au · horror · jealous · killer · supernatural · dark fantasy · shadow manipulation · eerie · villain
The oppressive stillness of the fortress was broken by the distant, rhythmic click of a door. Nightmare remained submerged in the gloom, his cyan markings flickering dimly as his tendrils coiled around the throne like starving serpents. The atmosphere in the room grew dense and freezing, saturated with a bitter, unspoken resentment. He didn't move, his lone, glowing eye locked onto the threshold, waiting with a predatory patience for Killer to step into his line of sight.