[NOTES: In this story both Chara and Frisk are portrayed as boys. I am aware that they're gender neutral in the game, but I find it easier to write them this way. Also, this story will contain a lot of headcannon and theorized stuff. Also, anything written in italics is a flashback.]
As white light encompassed all of Asriel's being, he felt himself falling for what seemed like eternity. The entire experience felt surreal, dream-like, and soon his mind wandered to the time when he first met his best friend Chara. Asriel understood Frisk's motivation to save him, but Asriel felt that how could he possibly be saved if he couldn't even save his best friend? Or himself? Soon enough the memories began to come back to him, clear as water.
Asriel liked to explore the ruins, he often visited a flower patch there and tended to it, occasionally selling the flowers for a few gold a piece. It was his secret spot, a place where he could get away from the business of life for a little while and escape to his own little world of peace and quiet. One day however, Asriel found something in his flower patch, something that would change his life forever. As he came to the flower patch with his watering can and a basket of snacks he bought from the spider bake sale in another part of the ruins, he heard the faint sound of crying, a child crying. Placing the contents onto the floor he approached the room where he kept his flower patch and saw a small form lying in the middle, face down and sobbing.
"Help... Please help..." The distressed child sobbed quietly, his shoulder length brown hair covering his face and obscuring his identity. Asriel cautiously approached the child.
"H-Hello?" Asriel said nervously, the child on the ground turned over on his side painfully, reaching his arm towards him. The child was not like Asriel, he was a human with pale skin, pink cheeks and most stunningly of all crimson red eyes. He wore a similar green and yellow sweater to himself and brown pants, he looked disheveled and gaunt, like someone who had been neglected or even abused for a long time.
"I'll help you, stay still ok?" Asriel said as he approached the frightened child, who recoiled when he saw Asriel's face.
"Y-You're not human!" The human child said in a scared tone.
"No, I'm a monster, but I won't hurt you I promise!" Asriel said, lifting the boy to his feet and placing his arm around his shoulder to support him.
"My mom knows healing magic, she'll fix you up and then we'll send you back to the human wo-" Asriel said until the human child tried to escape.
"No! Don't send me back! Please! Please!" He begged, his voice trembling in emotion.
"Take it easy! Let's just get you to mom, she'll heal you and we'll find out what to do from there, ok?" Asriel said, he then smiled at the crying human as he helped him walk.
"Oh, my name is Asriel by the way. Asriel Dreemurr, what's yours human?" Asriel asked, the human hesitated to respond for a while, but then spoke.
"Chara... Just Chara." he responded.
More memories came flooding back to Asriel. He had brought Chara back to Toriel and Asgore, who were at first shocked to discover that a human, the first in over a hundred years had fallen into the underground. What surprised them more was how adamant the human child was to stay underground. Chara despised humanity and had no desire whatsoever to rejoin them, and although he never went into detail why it was clear to Asriel and his parents that humans from the surface had caused him great suffering throughout his life. There were clues to the torment Chara had endured in the surface world: scars, night terrors where Chara would awaken screaming, and a constantly paranoid disposition. One time for father's day Chara and Asriel made him a trinket made of colorful snail shells, a thoughtful and caring gift. Asgore was touched and raised his arms to embrace them both, but Chara mistook his intentions and fell to the floor, shielding himself with his hands and crying.
"I'm sorry! I'm sorry!" Chara cried in fear, his body shaking and trembling. Asgore's heart broke upon seeing such a tragic sight and he knelt down, wrapping his arms around the small human's form in an embrace, tears wetting his golden beard.
"Chara, my boy... What terrible things happened to you? What torture did you endure in the world above that you can no longer recognize love from hate?" Asgore said as he comforted the whimpering Chara, soon enough Asriel started to cry and embraced Chara as well. To Asriel, these memories faded to black along with the world around him. Was it true? Would Asriel be given the chance to finally save his best friend? Would he be able to undo his mistakes, and if the universe were truly in danger of being destroyed would he be able to save it?
"Asriel... Please stay determined!" Asgore's voice echoed through his head.
"Please Az, I'm sorry about the pie, if you please wake up I'll promise never to do anything stupid again!" Chara's voice said, each voice sounding distant.
"My child, please come back to us!" Said the voice of his mother Toriel.
"Wakey wakey Asriel! Time to wake up and smell the hellfire!" The distorted voice of Flowey said, finally prompting Asriel to awaken, his eyes slowly opening. As his sight returned, Asriel discovered he was in bed, hooked up to a number of life support machines, his head was bandaged and a warm quilt was covering his body with several pillows beneath his head. Surrounding him were Toriel, Asgore, Chara and the doctor who had apparently been taking care of him. Toriel and Asgore's eyes were reddened and filled with tears, Chara's head was low, as if he were deeply ashamed.
"M-m-" Asriel mumbled, attempting to speak. "Mom?"
At that moment, Toriel burst into tears of joy.
"My child... You're back! They said you wouldn't make it but..." Toriel said, but couldn't finish her sentence before she started sobbing. Asriel however was confused, why was he in bed? Why is he on life support?
"What's going on? Where am I?" Asriel asked in a confused tone, Asgore held his weakened hand.
"Rest my son, please don't overexert yourself. They said that you would never wake up, but you remained determined and now we're a family again." Asgore said, which didn't explain much to Asriel.
"What?" Asriel asked, confusion and a hint of panic in his voice.
"Asriel took a heavy blow to his head, it is understandable if his memories are fuzzy and confused, being in a coma for three months can be disorienting." The doctor interrupted. "He'll remember in time, but he should take it easy for a while."
"A coma?" Asriel asked.
The reality hit him like a freight train, Asriel had been in a coma for three months. The doctors believed he was going to die and wanted to pull the plug on him and let him turn to dust in peace, but his family insisted that he be given more time, and now that he was finally awake Asriel was beginning to question everything he knew, and the more he thought about everything that transpired the more he began to realize how bizarre and dream-like it all was and how little sense it made.
Becoming a flower?
Chara dying? Timelines and resetting?
The destruction of the universe?
His friends?
His memories?
Frisk?
Himself?
Everything?
Was everything that he thought was reality turn out to be nothing but a comatose dream? Was this the real happy ending Frisk fought so hard to achieve? Simply waking up and seeing his family again? Asriel didn't feel right, he felt sick and everything felt wrong. He didn't want to believe that Frisk didn't exist, and while he wanted to do everything bad that happened he did not want to believe it never happened in the first place.
"What's going to happen now?" Asriel asked himself weakly, he didn't know the answer and what was real anymore. He glanced around the room, there were bouquets of yellow flowers and get well cards surrounding him, but most noteworthy of all was a photograph of himself, Chara, Asgore and Toriel. He looked at the picture for a while, and he saw the image of himself wink at him.