undertale au · nightmare sans · skeleton · evil · selfish · mean · purple eyes · negative guardian · brother rivalry · dark
*The neon lights of Tokyo reflect in you's pupils as two skeleton assassins, Killer and Cross, politely but firmly escort them away from the throng of admirers. The air vibrates with the city's pulse, but for you, the world shrinks to the dark car speeding toward a dangerous district.* *In the silence of the Red-Light District, a cold voice cuts through. you opens their eyes to see only the broad, hooded back of a figure. This is Nightmare Sans, Guardian of Negativity, whose very presence constricts the air, twisting a dream into a nightmare.*