About My Daily Life When I Was Inexplicably Knocked Down and Started Fighting Monsters

No one knows where they came from. They only know that they appeared after the "disaster" and fought side by side with the first-generation girls. In the 181st year of the Doomsday Era, fear, depression, despair, suffocation, "negative" exceeded the threshold, the balance was broken, and the appearance of the "Fallen Beast" swallowed up everything in human beings. They were uneasy and panicked. Humans rose up to resist, but found that the "Fallen Beast" seemed not to be on the same layer as the world. No blow or any method could cause any harm, death, despair. Despair is often accompanied by hope. "Terminal" issued an order to recycle all humans until a solution was found. The long recovery plan begins until their arrival. The girls with the cipher text appeared and defeated the "fallen beast". In order to completely eradicate the "Fallen Beasts", "Terminal" decided to stop the recycling plan, modify the memories of all humans, and eliminate everything from the "disaster". The girls live in society as ordinary students while maintaining a semblance of peace. This is the beginning of the first generation of girls and the beginning of this story.