Chapter 1: A Change in Fate

The golden hallway was quiet, disturbingly so. Light shone through in such a manner that the right sides of its occupants were completely enveloped in shadow, and neither of the two people within moved a muscle. Despite the fact that one didn't have any muscles to move, of course. The stale air that constantly drifted through the Underground caught in their throats, a constant reminder for one occupant of the melancholy of eternal life far beneath the reaches of the Sun. A kind of cold, calculating horror filled the hallway, an aura exuding pure evil and tension.

As lazy and laidback as he put on, Sans the Skeleton could not help but shiver in a cold rush of fear at the dastardly smile twisting the human's—Chara's—face into nightmare fuel. Ever since the second Loop, as he had come to call them, his nights had been spent sleepless, staring up at his ceiling in a cold sweat, the memory of Chara's evil ingrained into his very soul. He couldn't even forget it on the Loops in which Frisk was allowed momentary control of themselves again.

He swallowed a dry knot and clenched his bony hands into bony fists. "so," he growled, and blue flame sparked in his eyes as he cautiously watched his tormentor. "you've returned again. that looks like the twisted grin of a murderer who's burnt the world more times than any monster or human could count."

"You always know so much, Sans," Chara hummed, the grin widening. Had he had any blood, Sans' would've ran cold at the sight. "Too bad it doesn't serve you any good. You can't RESET. You can't SAVE. You can't do anything except watch me kill everyone over… and over… and over again! Alphys… Undyne… Mettaton… Toriel… Asgore… Papyrus… and finally, poor, innocent Frisk. And then you're stuck with the memories of it all! Tell me, how exquisite is the despair you always feel?"

"...you're a sadist," said Sans, refusing to let the demon's words affect him. The fire in his eye flared, and behind and above him, the image of a giant, horned skull blinked into existence. Its mouth opened wide, revealing a deadly laser that quickly grew in power and blue energy. "let's just get this over with. we both know how this'll end."

The two-faced bitch paused, her hateful smirk falling into a somewhat disappointed frown. "You're no fun, Sansy," she grumbled. She sighed and pulled a dust-coated knife from her pocket—ever her choice weapon. Sans couldn't remember a single Loop where Chara hadn't been carrying it, even when she was masquerading as Frisk in the Pacifist Loops. "Very well. I'll make your death nice and painful for you!"

Exclamation points momentarily popped into being above both Chara and Sans' heads, and the world turned black and white, leaving the two fighters in an empty void. The FIGHT had begun.

At the exact moment that the FIGHT void appeared, Sans' laser blasted forward through the blackness, aimed directly at Chara. The sadist giggled and rolled to the side, easily avoiding it. Growling, Sans summoned two more Gaster Blasters, loading and firing each at differing intervals. Every blast missed, however; Chara had infinite Loops of practice learning Sans' attacks and how to dodge them, and although she'd had a bad time the first hundred or so Loops, by now it was mere child's play to her. Perhaps even less than that. This was made clear as the demon rolled away from every single blast with miles of space between them, making her way closer to Sans with each dodge.

"you've gotten far too skilled at this," muttered Sans.

With a swipe of his arm, the Gaster Blasters phased away, replaced by a floating sea of bones. Chara paused at the sight, raising her knife for defensive measures. One by one, the bones all turned in midair so that they faced her horizontally. A moment passed wherein nothing happened, and then with a shout from Sans, they flashed through the air directly at her.

Chara, however, was unfazed by the onslaught of bones. She gripped her knife and quickly swept it through the air, knocking away every single bone and sidestepping any that came before she could regain her stance. Her arm moved so quickly that neither human nor monster eye could comprehend its speed. Each bone that fell to the black ground uselessly as a result of her deflections flickered and then faded from existence.

A cold bead of sweat rolled down the side of Sans' own skull. He lifted his finger up, and massive walls of bones rose around Chara on all four sides. One flick of his wrist later, they started to smash together. In their midst, Chara raised her eyebrow—this trick of the skeleton's was new. Examining the attack, she saw that in the corners between each column of bones, there was enough space to dodge through, although that would be eradicated in no less than two seconds. This information learned, the demonic human wasted no further time, and dived through the opening most accessible to her. Her speed was too great for the attack, and the bone walls slammed together harmlessly as she tucked and rolled to safety.

"Huh, whaddya know?" Chara sang as she picked herself up off the void's floor, making a show of brushing dust off of Frisk's striped shirt. "I guess what they say is false—you can teach an old dog new tricks."

Sans' flaming eye socket twitched. "shut up, demon. after so many loops, you can't expect me to believe that you never imagined i'd invent new ways to kill you."

"Oh, no, you're perfectly right about that," agreed Chara, her smirk widening. "'Cuz, you see, what I expect you to believe is that I'd never imagine new ways to kill you."

"huh? what are you talking ab—"

Sans' voice choked. His head tilted down to his chest, only to see his favorite jacket and his ribcage sliced open, spewing blood all over the void floor. Pain wracked every inch of his being. And the worst part of it all? That knife—the knife with which Chara had killed every single one of his friends, countless times over, many of which occurred before his very eye sockets—stuck into his skeletal body, right in the middle of the wound.

Pale, Sans slowly looked up at the smirking demon, who stood ten feet away. "you… bitch… you t-threw it while i was talking…"

"It's great that you're coming up with new attacks and all," said Chara, tilting her head to the side in a mockingly cute manner, "but you should really learn to not let your attention down in a fight, Sansy. Even saying a single word can pull your attention away, and once that's gone? Well… you might just get dunked on."

"you stole my friends' lives… you stole mine… and now you steal the single solace i have left, the only thing that keeps me going: my jokes…" As his body broke into millions and billions of tiny dust particles, Sans' blue eye flared momentarily the brightest Chara had ever seen it become. "watch out for yourself next loop, chara. i don't know how, but i will erase you from our lives."

Then the last of Sans' body broke, there came an unusual flash of green light, and the world blared back in full Technicolor. Chara was once again in the hallway, Sans' dust coating the floor in front of her. In the middle of the pile, her knife stuck up out of it like the hellish version of the sword in the stone. The demon paused, however, staring at the spot where her opponent had died.

"No soul's appearing…?" Chara murmured to herself, narrowing her eyes. "My STATs didn't raise, either… hm…"

Sending a calculating glare at the air above Sans' dust pile, Chara stood still for several moments, expecting to see a boss monster's silver soul appear and then shatter.

But none came.

"...That's strange," Chara said at last to herself, shrugging and pulling her chosen weapon out of the dust. She stuck the knife into Frisk's jeans' pocket, not bothering to wipe the dust off of it. She liked her weapons… dirty. "Well, no matter. I have a King to kill and another timeline to RESET."

Sans woke in a silent, emerald green void, unlike anything he'd ever seen in all of the horrible Loops he'd suffered through. His body floated in the middle of the void, the only organic material he could spy. There was, however, endless columns of white ones and zeroes, streaming vertically up and down randomly.

"what in the underground…?" gasped Sans, eyes wide. "is this… computer code?"

Floating aimlessly, Sans squinted at the nearest columns of ones and zeroes. During his time spent working with Alphys and W.D. Gaster on the Determination Extraction Machine, he'd come to memorize every character in computer code. It had been necessary for completing the fatal machine. Now, it served him well, giving him the ability to read the information streaming through this mysterious void, and from it he gleamed a disturbing insight.

Their world, the Underground, ran entirely upon computer code.

Sans wasn't sure exactly what this meant for his friends and the Underground in general, but within five minutes he'd learned enough to formulate a system of code that might be able to bring him someplace else. He reached forward with a trembling hand and snatched random ones and zeroes out of their columns; strangely, the ones he grabbed didn't seem to break the line, and instead simply replicated themselves. Within seconds, he'd arranged a pattern in such a way that he'd formed a command for a portal to open for him. He released the code, and it was sent up into the far reaches of the void, beyond what he could see.

For a long while, a time he couldn't keep track of, nothing happened. And then, just as he was giving up hope, a white tear in the world ripped through the void right before him, sucking him forward to it. His entire world went a ghostly white, and in the blink of an eye he found himself in neither the Underground nor the void; for he'd ended up in the surface.

An itchy feeling rose up in his bones, a kind of gravity pulling at his very SOUL, and Sans knew the time he had left was short. He couldn't even appreciate the beauty of the moonlight dancing across the landscape, of real stars twinkling in the night sky high above. A RESET was processing, and he would only have a few seconds for a chance to change the world. Sans desperately felt out the path with his SOUL, searching for someone with a resonance that would save them all. His SOUL lifted out of his body and pointed him towards the left, towards a state in the United States called Ohio. Not wasting any time, Sans phased to the location his Soul had picked up on.

It was nighttime in Ohio, around midnight, and he'd arrived in the bedroom of a young man sitting at his computer and typing on some social messaging program. Friends of his were typing back, joking around with each other. He was of medium height, with chocolate brown hair, his back turned to Sans. Unaware of the skeleton's presence, he continued his typing, hands moving with impressive speed across the keyboard despite not looking at it. He'd clearly done enough writing in his young life—Sans judged him to be no more than 18 years old—that he'd memorized the positions of all the different keys.

this boy… Sans thought, narrowing his eye sockets. i sense little more DETERMINATION in him than what the average human has… so why does he seem so important?

In the precious little time he had left before he was RESET, he searched through the boy's SOUL, and his eyes widened.

ah… that's why i was pulled here… an overwhelming KINDNESS…

Making up his mind, Sans extended his arm, and grasped the boy's shirt collar with his finger bones. The boy stiffened, surprised, and his head started to turn, but at that exact moment, the RESET went into full effect. A terrible roar built up in Sans' ears, a great whooshing of air filling the boy's bedroom. The world before Sans' eyes became a blurry multitude of images flashing backwards at mach speeds, as if the history of the world was on replay. The feeling of gravity acting on him grew stronger, and the roaring increased tremendously in volume until it was the only thing he could hear. Sans might've screamed, but he had felt this sensation many, many times before, and while it was never something one got used to, he'd adjusted enough that he could keep his dignity through it.

Then the world blanked out, and Sans and the human disappeared from the latter's bedroom. Not a trace of either being remained.