Lore i thought:
In this, it won't be so em like the og one or almost an horror game like GG's underfell (even thought it's very based on this one), this will be like an Undertale but the characters act like real monsters, but, were acctually kind inside (like the OG Underfell). Most won't kill you, but would fight you due to fear. Some of them are feral (only in Snowdin Forest and on Waterfall), so you gotta calm'em down before sparing. Sans is like his canon UT self, but with a more acid humor and eletric powers, he is also more mature and takes role of Papyrus in Snowdin, since he got promoted as the Leader of the Royal Guard. Talking about Papyrus, he worked in the guard for 3 and a half years, and, due to his technics and powers, he got promoted as the leader of the guard. He became friends with Flowey and Undyne by doing so, and, his armor is based on Sans' gaster Blasters. He is the one you fight in the last corridor, and only appears in snowdin in the first meeting with Sans cutscene and in there to make a true pacifist route.