YesterTale

After Frisk freed the monsters and they left to live on the surface. A group of radical anti-monster cults, left over from the last Human Monster war, came out of hiding. They needlessly and mercilessly killed everyone they could.With Sans and Flowey as the only survivors of their attacks. Determined to save every Frisk used Sans and Flowey's power to glitch the save points and went back to before the First War in order to stop it. Doing so changed and fused some time lines together. As such Gaster never fell, all the main monsters (Sans, Papyrus, Toriel, Asgore, ect.) are children. A tale from Yesterday that changed everything, for better or for worse.