Sans frowned; he could see her fighting Chara from the inside. Sometimes, her eyes would blink in confusion and recognition, fear and relief, before her gentle brown doe-eyes were overtaken with a flood of blood red.
Frisk tried to sing to him when she saw him; her voice often got drowned out but she knows that Sans knows now. He sang back in reassurance and defiance, to a person one in the same.
Chara taunted him, mocking him; Sans retaliates, shots firing from his Gasterblasters.
Frisk breaks free to input and all three collided in a split-second brawl.
Frisk dropped the knife, intending to give up for him; Sans saw and aimed for her heart, hoping to be quick and painless.
Chara twisted round, snatching up the knife, whirling back round to cut Sans down.
He skidded back, eye sockets wide with surprise, clutching the wound in disbelief. Looking back up, Sans saw Frisk cry out silently in anguish, before the expression steeled itself and she twirled round to push away from Chara, separating them, so she could proceed to grapple with her for the knife.
Sans grinned weakly and it was all he could do to keep his eye sockets open as he sank back against a pillar, sliding to the floor, and watched the silhouettes dance.
They spun and flitted back and forth before Frisk threw Chara down, pinning her to the marbled floor with the knife. She launched herself backwards, somehow keeping balance, taking off running towards her friend. Chara screamed out her rage, struggling futilely to dislodge herself, only to watch as Sans looked up.
He saw Frisk, tears streaming, hair billowing, hands reaching, a picture of grace and beauty and purity and innocence in every sense. He reached out for her; it was all he had left.
Frisk stilled and fell to her knees as she reached him and she smiled her darling smile, eyes closed and head tilted, and she fell forwards into his lovingly sweet embrace as bone that pierced her heart dissipated.
Chara howled furiously and wrenched the knife out of the ground, running to mutilate the small body in his arms.
Sans wouldn't allow that and his Gasterblasters fired once more.
He watched Chara's shadow detach as the light consumed her noisy corpse, unholy sounds erupting from the melting figure. The shadow moved, brushing over a button, and everything was okay.
And Sans could smile now.