Day 1 of trying to get my au noticed by the Undertale fandom
I have like 4 or 5 parts out of animatics for Brokentale on my yt channel but animation is hard so don't expect parts to come out frequently
Anyways basic lore and plot
After the 5th human fell into the underground, Alphys started experimenting with determination. She started out by using things like flowers before using it on any actual monsters, thus creating Flowey. After this, she wanted to try testing some other chemicals to see how things would react to them. Determination and what's known as Insanity go hand in hand with humans. Too much Insanity in a human can result in them basically being a genocidal freak. Usually humans have the perfect mix of Insanity and Determination. After Alphys learned that Insanity was also a core part in a human soul, she wanted to experiment with it as well. However this chemical only came in the form of a steam. So in order to keep everything safe, Alphys needed to make sure everything was secure. But there was a crack in the door. Alphys figured that out too late. The gas mask she had on wasn't secure either, causing her to be the first one to go Insane.
Alphys ran out of True Lab to see Mettaton outside asking if she was okay. Alphys panicked and ended up ranting on what happened. But as she was talking, the Insanity came out of the door. She had inevitably inhaled it, and started acting strange. Nothing much at first, just seeming weird but then she went to the point of harming others. She didn't want to deep down so she ended up hurting herself instead.
Meanwhile, the gas began spreading through the underground and having pretty much nowhere to air out, every monster would eventually go insane from it.
Once the gas spread to the Ruins, monsters started acting strange to Toriel. The monsters would often fight or even kill each other. Toriel didn't know why they acted like this. Until she began to feel insane as well. After the sixth human ended up dying, she grew an obsession with protecting the humans. So much so that she killed every monster in the Ruins.
Once the Insanity spread through all of the underground, it seemed hopeless. The world was broken.
Only one monster wasn't affected. That was Napstablook due to them being a ghost. Mad Mew Mew and Mettaton had already become corporal before the Insanity broke loose, so they still went insane.
Sans didn't want to be insane, so he thought maybe there was a way to stop himself from being insane. So he started to do drugs. And he became addicted.
After Frisk fell and saw the current state of the monsters, they wanted to fix it. They wanted to fix what had been broken. They managed to make some monsters come back to their senses and start to be at least a little more sane.
It turned out that Flowey had also been the direct candidate of being tested with the Insanity.
After everyone seemed somehow sane again, Flowey came. He took their souls and became Asriel Dreemurr. After Frisk managed to defeat him, the barrier was finally broken. The monsters were free and the Insanity could air out. Everyone managed to be sane again and then everything was fixed. Alphys, knowing all of this was her fault felt as if she could never forgive herself but after her friends said that it was just a mistake and they forgave her, she managed to feel at least a little better.