The War between Humans and Monsters raged on. Both sides had heavy casualties, but it seemed as if the Humans were gaining the upper hand. "Monsters! Push forward!" King Asgore yelled, fireballs tearing from his trident. Reinvigorated, the monsters refreshed their attacks and started to push the Humans back. A wave of magic tore through the Human ranks. "CHARGE!" yelled Asore, cutting down several Humans with one stroke of his trident. However, the success of the Monsters was short-lived. A fresh army of Humans appeared over the hills. Waves of arrows flew towards the Monsters, wounding not a few.
A human male child of ten years wandered near to the battle. He did not care for the fighting, only for the amusement he might obtain by getting past the ranks of the Monsters. "Aha!" the child murmured, spotting a vine hanging off a mountain. As the child climbed the vine, he had a strange feeling. All of a sudden, he was enveloped in crackling blue energy and he lost his grip. "AAAHHHHHHHHH!" cried the child as he plunged deep into the Underground.
The child awoke in a bed of golden flowers. He observed his hands. His right hand seemed to be glowing blue with energy. The child pressed on, and noticed as he walked that the environment changed as he walked. At first, there was rubble everywhere. Then, it was cold and snowy. Next, he felt heat radiating from the ground. Finally, he came to a large door. The words "CORE" were written upon it in big, neat lettering. The child rubbed his flat stomach. He had not eaten for days. As he stepped through the threshold of the door and felt the cold metal floor, he suddenly saw black spots in his vision, his head spun, and he lost consciousness.
Royal Scientist W.D. Gaster spotted the child's unconscious form at his door. He rushed over, his first thought being to deliver him to Asgore. This child's SOUL would be the first in the endeavour to free the Monsters from the Barrier. Then, he felt pity for the child. Surely, he could not murder such a young, innocent youth? Gaster held the child hesitatingly. "No, Asgore would not have the satisfaction of taking a SOUL." Gaster murmured to himself. He carried the child to an empty mattress, prepared some instant food and a flask of water. Then, he waited for the child to wake up.
The human child woke up. "Wh-where am I?" he saw Gaster looking concerned. "What the- who are you? Where am I?" Gaster looked kindly at the child. "Worry not, young human. I have no intentions of hurting you. You are in the Underground, and you have been lying in a state of near-starvation for a week. Just today, the humans sealed us in with a magic spell. They created the Barrier." The child nodded slowly, trying to digest this information. "Who are you, sir?" Gaster gave a flicker of a grin. "I am Royal Scientist W.D. Gaster."
The human child knew some about the Barrier. It was never spoken off back on the surface but he knew that it required SOUL power to be destroyed. "Could I be your son?" the child asked awkwardly. Gaster looked at him delightedly. "Consider it done, erm, what even is your name, my son?" The child drew himself up proudly. "Samuel David Cho. Most call me Speedy." Gaster thought for a while. "Okay…so…Sam, no, Speedy, would you like me to introduce you to the Underground?" The child, who we must now call Speedy, nodded. "It would be a pleasure." He said. "Then we must go now. Remember, never let go of my robe. Should you get attacked by the other Monsters, I'll teleport us out of here. Now, come along."