I have done Bane's one, but it's so much more complicated and long that i want to make it well, not just a big text, i al already busy with Rubt comic so laybe i'll make a comic later for Bane. Dunno.
Oh and, can't choose which outfit is better ? (I forgot Black eyes background in the 2nd pic
Anyway here's Nerya lore, it's a more simple story :
most Sans in AUs are either heroes (like Dream Sans, etc.) or villains (Killer Sans, Nightmare Sans, etc.), and she always wanted to throw hero parties.
At the beginning of her adolescence, she found a small group of friends who shared her ambition, so they formed a small group of heroes. Well... they didn't do much; they wanted to imitate the greats, doing little things here and there, but no big battles.
But Nerya had an anger management problem; she didn't know how to control her emotions. So sometimes she was a bit rude, which isn't really a hero behavor .
One day, they attempted a riskier mission. They heard about a group of villains who were destroying an AU, so they went to save the AU/timeline. However, being far too weak, they quickly fled.
One of Nerya's friends was caught. Nerya was closest to her at that moment and could clearly have helped her. Her friend asked Nerya to help her, but she chose to run away out of fear. She choosed herself instead of her friend
Since then, we never saw that friend again, and Nerya was blamed for what happened by the other members of the small group. They told her: "You weren't even able to save your friend, and you want to be a hero? You're dreaming!"Etc., etc...
So Nerya found herself alone. She couldn't be a hero... maybe that meant she was a villain? She not became à villain because she was broken or so (like Ruby). What hapenend did hurt her, but if she decided to try to be a villain was simply because she thought it was her place, and to have another group.
So she did the same thing again, joining a group of villains. Well, I'm missing some details here, but basically, things went badly here too, and so she had to abandon that group of villains.
She get abandoned. Twice.
She decided she wasn't going to live anymore to be accepted, to depend on others, or to be part of a group, and she was going to live for herself. So now she explores the timelines, doing what she wants in each one, having fun, promising fake friendships before leaving without a trace.
But, she's not sure to be really happy with this life.