there's something about papyrus missing from deltarune that feels really...intentional. when he's mentioned in the first two chapters i figured he would get a small cameo later in the game, but after chapters three and four im starting to think that papyrus' absence actually might play a much larger role in the story.
i dont have a lot of evidence to back this claim up, but...just follow me for a sec. think about who papyrus is and the role his character plays in the world of undertale.
papyrus' main goal throughout the entire game is to be popular and make friends. he's very loud, outgoing, and takes up a lot of space. multiple characters in snowdin mention him, and he even managed to befriend undyne who doesnt seem to have many friends due to her tough demeanor.
if papyrus was in hometown, i think we would know it. he's too extroverted to not have an impact on this quiet little town, so maybe he was never there in the first place. it's also super weird that sans mentions him very vaguely in our first interaction, and then seems to have completely forgotten the conversation the next time we see him. something fishy is going on...
i have an absolutely crackpot theory that papyrus has something to do with the eggs, but my evidence is speculative at best. honestly i just miss that funny skeleton guy. tony please give him back.