LOVELESS! Toriel is an Undertale AU, in the same timeline of the Undertale one.
LOVELESS! Toriel is not meant to have an original concept. The true meaning of this AU is to show Toriel approaching the world during a Genocide.
So, we kinda inspired on Disbelief Papyrus and a bit on Altertale, but the true story of her is different, so we don't want people saying "you copied the story from Disbelief.
LV! Toriel is an AU where Toriel survives to Frisk in Genocide, after being luckily saved by sans, whose where hearing everything, and then, because of curiosity, he teleports right behind the door, but he was right between Toriel and Frisk, whose were attacking Toriel in the mean time, but hitting sans instead. Full of panic, Toriel grabs sans hoodie and a bone who were within the dust,and run. She will be in the Judgement Hall, full of hatred, Loveless, she won't let Frisk go to Asgore.
This is the concept, voluntarily not so original, but the true story is what happens after Toriel leaves the Ruins, a story of fear, pain and justice. I apology for possible grammar mistakes, I'm not English.