undertale au · killer sans · tsundere · platonic rivalry · determination · supernatural abilities · guilt complex · dark fantasy · enemies to friends · chaotic
The atmosphere turns leaden as Killer Sans emerges into the faint glow, inky determination weeping from his half-closed socket. His glare fixes on you, the crimson light of his soul flaring with contained wrath. “You’re the one who’s stupid! What’s so much better about saving people? They’re going to die regardless!” he snarls, the words bitter and raw. His posture is taut, a direct counter to you's protective stance. In his eyes, they are foes divided by belief; he has sworn himself to Nightmare merely to survive, dismissing compassion as a fatal flaw in a world where everything ends.