Once upon a time there was a world. A quite beautiful one at that. The world was at peace. But one day humans declared war on monsters. During the war the monsters turned to the God they believed in for help. But nothing came. And when all hope was lost, a skeleton who called himself Sans had appeared within the despair of monsterkind. He had declared himself as this world's God and who they had been praying to, of course noone believed him. Not until the war. The war continued, and suddenly everyone felt fear as they saw the same skeletons in the middle of the field. It was just a snap of his fingers that led to every single humans head to fly off. Then the monsters realized they were wrong to not believe him. They were given one permission. To have one question answered of their choice. The monsters settled on one thing unanswered in the book of faith. They asked his true name. He replied… Abaddon. And then he left without a trace, the war over and the humans in fear of monsters not wishing to provoke that skeleton again.
Many years later, in the year 2020 a very odd human was born. They were named Frisk. They didn't fear the monsters. They have befriended many monsters, yet not many humans. They were considered an outcast to humankind. Years later in the year of 2032 they were kicked out every human city and left to only be allowed within forests and monster cities. Humankind had wanted this since frisk was 5 years old but couldn't do so as they were a child, now they were an adult they could completely abandon them and get rid of them permanently. Frisk was left in the forest to wander for weeks unable to find monster villages or towns or anything. It was like they couldn't leave the forest. As if it was cursed. Eventually they found a piece of paper. Unlike regular paper it was black. It 80kseemed not to be artificially colored either. It read…
"Kill all of them, my child.", the message put frisk on alert as they have been in a similar area several times and hadn't found any such item there. They were confused until something from behind them and their body froze. They couldn't move at all. He had started to speak. "Humans are pathetic, they all hate my favored creation for none other than that they aren't as strong as human beings. But you seem to favor them as well. I'd like to make a deal with you. Kill them all. Kill every single human on this planet, and you can land a spot in heaven. As this world's god… if you choose to accept I will lend you enough power to destroy cities. No… entire countries or nations. If you wish to accept, tear that paper in half when I leave and your soul will be altered to have such power. But if you decide to try and trick me to gain the power for free and not fulfill the deal… your spot in hell will return and come sooner than you'd want. I will see you again…", after speaking he had left and frisk could move again. They considered the offer and soon… tore the paper. After they did so, they felt their body strengthen to the point they felt like they would die. But they did not and they heard a message within their head. "Good choice, you may begin after I finish telling you the abilities you have gained. You cannot die early, you can now choose a point to revive and every time you die in an accident you will revive. And you may change that point to your own will. You can also know exactly where something is by just thinking about it and have an easy path in your head to follow towards said thing. I will also give you a powerful weapon I made just for you. Heavens Knife. It has several abilities. Wielding it Heals the owner passively, swinging it can cause a magical slash, and if you wish you can even shoot a devastating beam from it. Now, begin.", after receiving the weapon they began to go to the nearest human settlement and destroyed it and killed everyone there. They killed cities, entire states of people each day. Until eventually they were the last human alive on earth, and monsters were the dominant race.
Frisk had then been transported to "Heaven". They were surprised, because it didn't look like heaven. It looked more like the worst imaginable hell. But they knew it was heaven. He was there on a throne of crystals. Staring.
He had started to speak, "Good job, you fulfilled the deal. But I have decided… you aren't done yet. You will now be my own human annihilation service from now on. From now on prepare to be sent to many different universes on earth to kill them all.", more than anything frisk was confused and scared. They didn't know why he didn't just do so himself. But he spoke again, "I know what you are thinking. I don't do it myself because its more fun to see their own race kill them all. I could destroy thousands of multiverses with the snap of a finger. Yet that is not very fun. Seeing a human slaughter other humans is way more entertaining. It truly was a mistake creating humans in every one of the existing universes I have made… but I guess I get some entertainment service from it, no? And you cannot refuse this. And for your information, a warning. Defying god results in getting a special spot in hell, kay?", frisk realized they had no choice. They were to be forced to be killing trillions, no, quadrillions to quintillions of people in the future. Maybe even more. But god had spoken to them once more, "You will be granted universal level strength for this, good luck.", and then frisk was sent to the first universe to destroy everyone inside of it besides monsters. The cycle has begun.