BB!Sans/Relationships

=== BB!Papyrus ===
Papyrus is Sans's younger brother. Based on his so far only appearance, Sans is depicted as a cruel, poor brother who only sees Papyrus as a passing amusement. Unlike all the other skelebros, Sans and Papyrus have a very unhealthy abusive relationship, as Sans is very unimpressed with being related to Papyrus. They're shown to never get along, as Sans has a bad temper and is often seen snapping at and insulting Papyrus, sometimes even physically beating him. It is shown Sans genuinely hates him and only sees him as replaceable entertainment. He is completely apathetic to Papyrus's misery, almost seeming to even enjoy the latter's anguish, hinted at when he was describing him to ST!Sans and Gaster via "wears a sweater, cries all the time, bit of a whiny bitch".
As described by the OG BB AU creator, Sans is not amused that he is related to Papyrus and often takes his anger out on him.