He used to be renowned across the Underground as a friendly, chatty fellow, making friends everywhere he went. He had a charm in his voice, the twinkle of his gaze, and there was never a monster that did not feel welcome in his presence, even with his occasional, good hearted pranks.
His welcomes these days were less anticipated.
While puzzles were notoriously Papyrus’ game, Sans has taken them up himself, of late. His traps were the kind you never waved to encounter, because there was no way out of them, and far worse than killing you… They kept you alive. They drew out your last measure of despair, while you waited to be found by its creator.
And when he did find you, his smile was no longer one of friendliness and mischief. The Hunger lived in his devious, delirious grin, and it was sure to be the last thing you saw in this world.
Besides that damn axe, of course.
Yes, Sans had his good sides, even in the world that had stolen his mind and his wife. His pranks and jokes were cruel and murderous, now, designed to create fear in the souls of other, lesser monsters as they fled the hooded spectre, the hunting, hungering best, but there were times, when the gold of merciless, mutated justice fled his gaze, and left behind the softer, more fleeting light of his patience.
That side was meant only for his brother and beloved, precious daughter, for the memory of his departed bride. They received the best of him, all that remained of his kindness and the good in his diseased, scarred soul.
None but his family would ever see this side. The rest of the Underground is the fuel to prolong the lives of his loved ones, blood for his hands and meat for the bite of his razor sharp blade, and when outside the influence of his family…
There is nothing left of Sans the skeleton but his renowned grin, and the echoing, hellacious cackle of the Hunger from deep within.
Within Sans’ shattered skull glows the evidence of his madness, his separated mind; his magic has divided, Justice and Patience two separate entities in his psyche, and are shown, together or separate, in his varying moods.
Before the Glitch and the Hunger, he was married to Frisk, and had managed to concieve a child with her before forcing her to leave the war-torn Underground. Her loss affected him more than even the Hunger, and cracked his soul so deeply that any further damage would instantly kill him.