YAMIADude asked:
"Is there a Nightfall Frisk? If so, are you guys friends, enemies, ect.? And what do you think of them?"

Well ya see. Nightfall Frisk did exist, but they gave up their soul to break the barrier once and for all. Unfortunately, since our au had one of the most resets recorded, the barrier became stronger and Frisk's soul wasn't enough.

After Fire broke the barrier, her soul brought back all the other fallen humans, and Asreil. Frisk was losing DT, and switched places with me in the void. (I was only have in the void while following Frisk and Fire through the underground.) And before my very eyes they- th- ey-...
Turned to dust.... It wasn't their fault for the genocide runs. The first time I actually saw who I consider a sibling, was the last I saw of them.