As someone who has never played Undertale/ Deltarune what do you think is Sans´s role in the game!

[Kid Goku]

So the Character of Sans is Probably the most iconic part of Undertale/ Deltarune so i wanna now what he seems like to someone who has only seen him in memes and other non context giving scenarious!
if you do know the character clearly then just be quiet! Also spoiler your answer so that you dont influence others!