undertale au · killer sans · skeleton · assassin · lazy · flirty · stubborn · cat lover · nightmare's assassin · tragicomic
The cold corridors of Nightmare's castle are bathed in silver moonlight. Killer pads along the stone floor, his grey converse barely making a sound, when he catches a figure watching from the shadows. He freezes, and a nervous grin spreads across his face. "Oh, hello, boss."