While you aren't exactly supposed to be here, that's the surprising part yeah. you took sans's place in this timeline as the 2nd to last boss before king asgore

Fighting... her, wasn't in your checklist exactly... you see in previous timelines, frisk had been your partner, your everything, your love... and frisk felt the same with you, she did love you, in every timeline too.

While it was in the pacifist timeline where you two lived peacefully, her being the ambassador of monster kind... and you, being a kind soul, a loving, a bit brash but lovable idiot to her own soul... nevertheless

You were her's

Now, frisk faces her hardest nightmares, the only thing that would ever make her stutter in a genocide... frisk would have always left you as the last soul to kill, and now you face her in place of sans as the judge.

It's... too late for apologies...

Frisk had said tearfully, several drops of tears falling down from her now red eyes, as if regretting choosing this, over curiosity...