I use the attack write,  ChaosDancer12 used edit and add scenes.  Battle was won with publish. Enjoy

"Who were the children that fell before?"

Sans paused, from where he was making lunch for the three of them. Papyrus was out, and he would be home soon, having gone out to pick up supplies from a thrift store, and the dump. They did not have everything that a human child needed, and he knew that Frisk would not stay here once she had fully recovered.

"The first child... was Chara, he was adopted by Asgore, and his then Queen, Toriel." Sans said, and Frisk blinked.

"Toriel... like the goat monster in the ruins?" She asked, and he made a face of dislike at the name.

"Unfortunately, do try to not mention her name, as she is very unliked outside of the ruins, due to her obsession with humans." He told her.

"Okay." She said, having a feeling that the dislike was for a good reason.

He told her the sad tale of Chara, and Asriel, both loved by the monsters, even if Chara was human. And Asgore's rule about humans, which was ignored, unless the humans that fell, were murderous.

"That's.. sad." Frisk said sniffing.

"Just be careful when you're wondering, The Captain of the Royal Guard, Undyne, is a hot head, and will hunt you. She lost her parents to one of the children who was... influenced by Toriel." He told her.

"Can't we all just be friends?" Frisk asked.

"It would be nice if we could, but it doesn't always work that way." Sans chuckled.

"What if I... flirt?" Frisk said, giving him a thumbs up. Sans stared at her, and she sighed, dropping it.

"You're a kid, in stripes. Anyone that flirts with you, I will personally dust." Sans said, with a smile that the grim reaper would be proud of, Frisk paled, and she nodded her head.
Right, that was a bad idea.

They spent the rest of the time discussing the rest of the children, to the ones that adapted, and lived happily below, to the murderous fallen ones that made people fear humans, to the feelings that the peaceful, and murderous children shared, of someone, or something, watching over them...

Later, Frisk stared at the bowl of rather good soup, silently, could.. she survive down here?

She wanted to see the sun that she could no longer remember, to find out who she was. Was Frisk even her real name?