Subnightmare Stories

What if... when Error fell Nightmare fell with him? What if... Error had siblings, but they aren't the ones you'd think they would be? What if... Error had a lover..? H...

My other AU multiverse where passive and Nightmare are in a relationship. They raise the bad guy children as their own after finding them in horrible situations. (Nightm...

I got this idea from sans from undersing so the credit for this idea goes to them well the dragon idea at least but idea that nightmare turns into a dragon is all me! in...