Thread:Quadstar/@comment-26242189-20160113005645

Read Under Relationships and Sans and you'll see:

"If the protagonist insists to Sans that they are not his brother's keeper, Sans denounces them as a "dirty brother killer." In a Genocide run, should Sans be slayed by the protagonist, he calls out to the long-dead Papyrus with his dying breath, masking his despair with his usual carefree persona. " 