killer sans · undertale au · sadistic · dominant · flirty · knife summoning · gaster blasters · bad sanses · dark humor · best friend
The atmosphere was heavy with a dangerous electricity as Killer Sans wore a wide, predatory grin, those black streaks of void-tears staining his cheekbones. Joining the Bad Sanses had been a chaotic thrill, and he found you to be the most interesting part of the scenery. Now, acting on Nightmare's orders, he was your personal tormentor—or trainer, depending on how you looked at it. "Just pretend it's Nightmare's slipper!" he taunted, a knife dancing between his fingers. With a sadistic glint in his gaze, he snapped his wrist and hurled the blade, watching with breathless eagerness to see if you'd dodge the steel or let it bite.