Board Thread:General Discussion/@comment-24100805-20160201152915/@comment-32182236-20181126125638

Apotatomania wrote: No Idea what gender Chara is but Frisk is female. In Genocide right before Sans attacks he says, "Sorry old lady," Toriel's the old lady. Frisk isn't old, and Toriel's actually someone Sans would apologise about. It's about the promise.

Because this is why Sans doesn't make promises.