Chapter Text
Long, long time ago...
Monsters were sealed in to the Underground by humans...
The monster's king, Asgore, wanted all of them dead.
If he could get seven human soul, he could have freed all of them.
But unfortunately, this is not how it ends.
One day, a human with her little baby went to Mt. Ebbott. She knew about the legend, but she didn't care. Even if there are really monsters down there, she said to her husband one day, they can't escape the underground. Altough, I feel sorry for them. Her husband told her many times not to climb the mountain with their baby. They're too small, too little. It can be dangerous, he said. But she didn't listen. She wanted her little baby to see the beauty of the mountain and nature. It was indeed a beautiful mountain, maybe because they were monsters down there.
The woman, with her baby on her arms, climbed and kept walking until she found an entrance. A cave, she thought, reassuring her child that nothing bad will happen if they stay together. But unfortunately, fate decided otherwise. When she entered the cave, the woman tripped down a hole she didn't see. It was indeed too dark to see what was inside but she wrapped herself against her little child in order to keep them safe.
If I die, what will you do all alone? I'm sorry, my love... Forgive me.
Her head was hit by a pointy rock of the cave and she died immediately, still holding her child nonetheless.
When Toriel did her routine, to see if any humans had fallen, she was shocked to see blood on yellow flowers. "Poor human...she didn't make it" Toriel kneeled down on the woman's level and examined her wounds. "Poor human...I wish I could have helped you...Mh?" She heard something, a muffled cry on the woman's chest and she removed the blood-tainted sheets surrounding her.
"What is this? A child?!" Toriel took the little baby on her arms. "They're so tiny and full of energy...Why your mother came here and left you all alone, my little child?" Toriel held the little child and sang softly a song to make them asleep. She then observed the woman's lifeless body and noticed that her soul had emerged.
A bright orange soul was glowing in the Ruins. "I won't let your soul be captured by him. I promise. I will take care of your soul and your baby for you." Toriel took the soul in one hand, floating right a few inches on her palm, and kept the child on the other arm. Good, they're still sleeping...I wonder what's their name, Toriel saw that the blanket covering the baby had a name stitched on it. (y/n), is it? "Very well, my child. You're (y/n) and this is your new home now. I hope you'll like it" she then proceed trough the Ruins, the others monsters -mostly froggits- were curious about the soul and the little thing that she was holding, but Toriel knew better to let them know what happened; even if they weren't dangerous, she couldn't trust them enough.
I must protect this child from any harm... When she arrived home, she locked away the woman's orange soul, to keep her safe, and brought the baby in a child's room. "Umh..I'm afraid I can't let you sleep all alone, my child. I suppose you need to stay with me, until you grew up enough to walk by yourself" she smiled at the baby, who was know smiling and laughing, trying to touch Toriel's face with their little hands.
Toriel returned back to where she found the woman and gave her a proper burial. "I won't let your child forget you, you'll be remembered, brave human". She stayed for a while, watching the tomb she made, until the child started crying. "Ssh, it's okay, little one, I promise. Stay with me, and nothing bad will happen to you".
And Toriel kept her words. The child, (y/n), grew up healthy and well, and never questioned her mother. They, for sure, were curious about everything and Toriel did her best to answer at every question with a smile. But as they grew up, they became curious about the basement downstairs. Her mother always said them that it was a dangerous place, and prohibited until they were older. But now they were seventeen and altough they never rebelled, they wanted to know what was going on down there.
"Mom, why I can't go there? I'm older now!" (y/n) said, helping Toriel baking cakes. "My child, I know what I said when you were younger, but it's...complicated. Why are you so curious about that place anyway?"
"I started dreaming about it and became curious. Even if everything was rather...orange. And I heard a voice...It seemed familiar but I couldn't quite understand what they said" Toriel stopped what she was doing and stared at her child in shock. Orange? A voice? Could that be...? "My child, I think it's time I show you something. Something about yourself and how you came here" Toriel cleaned her hands in a sink before going out of the kitchen. "Wait, mom! Didn't you say I came here because I fall down when I was little? I don't remember much..." (y/n) followed her outside and at the entrance of the Ruins, where everything started. "You did fall when you were little but...you weren't alone."
"What? So I wasn't alone? Who was with me?" Toriel didn't answered, but showed them the tomb. "The human who was with you didn't make it. I explained to you already what happens when a monster dies, right? They became ashes. Humans did not. So when I found out you and your...this human I was checking if both of you were alive".
Toriel sat down and looked at the tomb with shiny eyes, almost choking on her words. "I didn't...know she died. I found you with her, you were just a little baby, unaware of what happened...I...didn't want you to suffer. I wanted you to be happy and well. I know she wanted too..." (y/n) sat down next to her as well. "But I don't understand..who was her? Why did we fall?"
"I'm afraid I don't know the reasons behind it. All I know is that...your...mother, your real mother, fall down with you, but only you survived" Toriel watched (y/n)'s expression to see something, anything that could make them hate her, because she didn't tell them sooner. "I'm...confused. She was my real mom...I still don't understand why we fall down here! It's not..that I didn't want that...Mom, you've been so kind to me and always treated me like I was yours. I'm not mad or angry...Just confused. I know I'm a human because you said that to me and that we have peculiar souls...Wait.
You told me that human's souls are what we need to go back to the surface right?" Toriel watched them with a confused look on her face. What they were planning to...?
"Yes, my child. But I've already told you the story of Asgore and monsters". "Yes but..hear me out, mom. What if we use my real mom's soul to set us free?"
"No, my child. That is not possible. What Asgore did was wrong. It was wrong killing humans, it was wrong..even if they killed---" (y/n) hugged her tight. "I know mom, but we can be free. And I want to see the surface and explore it with you"
"Why? You don't like this place anymore?"
"It's not that--I mean, I love the Ruins, I love you, mom. But...I know that there is something else...Is it right? The basement..." "My child..." Toriel sighed, and got up from the floor and offered (y/n) a fluffy hand. (y/n) took it without heistation and let her guide them through the Ruins, to home. "It is better explain better to you at home. I won't lie this time. I will tell you the truth about everything. And about your soul's mother".