i think sans has 2-B tier via soul hax
one time flowey says "He would probably invite his garbage brother, you know smiley trashbag, ...say if i have ONE piece of advice for you...DON'T. let his brother. find out ANYTHING about you, he'll....well...let's just say....he's caused me more than my fair share of resets, stay away from that guy." So sans has fought flowey maybe multiple times.
And sans is still able to remember things from resets which would be type 1 acausality.
"You already heard my spiel haven't you?"
"I supspected something like this..."
"You're always acting like you know what's going to happen."
"Like you've seen it before."
Sans, Flowey, Toriel, Papyrus, Mettaton, and Asgore all have this ability as they remember stuff too so they too would have type 1 acauslity.
but what do you all think about this? <ac_metadata title="Undertale Revision" related_topics="Undertale|Sans|Flowey|Toriel"> </ac_metadata>