Chapter Text
It started with Papyrus finally getting to meet Mettaton in person, and the realization that their worlds had changed after it.
Sans couldn't count the number of times that Papyrus had asked about the little things, like if his scarf looked sloppily thrown around his neck, if his battle body seemed to be out of place, even if he seemed like a dateable person... Not that the older skeleton minded all this. After all, Papyrus had finally met his soulmate, after ages and ages of searching and hard work. He was happy for him, though he could have hoped for someone more... Humble, than Mettaton was.
In the Underground, monsters all had a soulmate, destined for them and them alone. While it may have proved impossible to find these soulmates under normal circumstances, it seemed like fate had worked a way around this.
All monsters saw the world around them in vibrant color, much like the humans that lived on the surface.
... But there was one little thing.
One color would elude them, and in its place, they would see only gray, rather than the vivid tones they might see otherwise.
The color that all the monsters were missing was the eye color of their soulmate.
Sans shook the thoughts of meeting a soulmate away, instead focusing on Papyrus, and whatever thing he was talking about now.
"... and, Sans, it's so different and pretty now! I can see all these different shades of pink that I never saw before, and I do believe that pink is my new favorite color! What do you think, brother? Should I change my wardrobe?" The younger skeleton was gushing, raving about the new color he could see now that he had finally met his soulmate, who happened to be the star of the Underground, and the only monster that had pink eyes, as far as Sans was aware, at the very least.
In hindsight, he really should have seen this coming. Despite all his doubts about his brother's newfound soulmate, even he had to begrudgingly admit that the robot complemented his spaghetti-loving brother quite nicely, and vice versa.
"Well, I should get going! I do not want to keep him waiting, and we do have a movie to catch!" Papyrus' voice cut Sans' thoughts and pulled him back to reality, giving his brother a lazy thumbs-up.
"Ya look great, Paps. Have a fun time, pet rock's rootin' for ya." The older brother turned the 'pet' to face the departing skeleton, waving for himself and for it.
Papyrus' smile only seemed to grow, and he gave a hearty laugh before bidding him goodbye, practically skipping out the door and closing it behind him.
Sans' smile faded a bit, watching his brother leave. Once he was sure the other wouldn't turn back to retrieve something or say one last parting phrase, he let out a hefty sigh, slumping back in his chair.
Papyrus was still just a young adult, but Sans was glad he'd found his soulmate already.
On the other hand, the older had had a harder time in his own search, which he'd long since given up on. It wasn't as if he didn't want a soulmate, the idea of someone meant just for you, and having that much of an impact on someone's life had excited Sans when he first heard about the entire concept, and for much of his teen and young adult life he'd thought of schemes and plans of how to meet this soulmate of his.
Sans was capable of seeing every color, every detail of the world and every tone, except for the vibrant red that his brother seemed to wear so often.
Of course, it wasn't really the lack of color that had bothered him. Other than making him blind to his brother's (former?) favorite color, and making it difficult to tell hearts apart from spades when he played cards at Grillby's, it wasn't any real hinderance to daily tasks.
No, what made it difficult for Sans to bear, was the fact that he'd searched almost the entirety of the Underground, and only a few monsters had eyes of the same brilliant crimson shade that he was looking for, but none of them had sparked any sort of change in his vision, even... Even when he met Toriel, face to face for the first time.
Red grumbled in annoyance as he rolled off of his mattress, the shouting coming from downstairs being more than enough to tell him that he slept in. He glanced over at his clock out of instinct, though, the numbers were a pale shade of blue, making it extremely difficult to tell the time.
It was almost like Boss was taunting him with this clock, having come home one day with a smug expression on his face, and the timepiece in his hands.
Red stood up and stumbled around the room when aforementioned skeleton yelled from downstairs once more, causing him to get dressed in a hurry.
The clock did raise some questions though, and its presence had made Red think about his soulmate more that once.
For example, who the hell had blue eyes? Everyone he knew had either red, orange or yellow, with little variation. There was the occasional purple, in cases like Grillby, or his daughter's girlfriend, but other than that, Red had never met anyone with the striking blue eyes that the universe told him his soulmate would have.
It frustrated him to no end, almost as if the universe was taunting him too, giving him an obvious hint like their damn eye color, but leaving him to figure out who the hell had blue eyes .
He was pulled from his thoughts when Boss yelled one last time, and hurried out of his bedroom, ready to start on another day of sentry work.
For two years, every day, at the end of his sentry shift, Sans would stroll up to the large, wooden door at the end of the forest, trading jokes with the woman on the other side, who came off as kind, humorous, and gentle. Days turned into months, and Sans felt himself becoming more and more sure that she was the one, especially when he had discreetly asked what her eye color was, and she had simply responded with "Red."
When the human finally left the ruins, having somehow convinced their goat mother to come along as well, Sans finally got to see her.
He could almost feel his heart drop when he realized it wasn't her.
But then, knowing who she really was, it made sense. She had already found her soulmate, long ago, quite possibly before Sans was even born, and she had left him. There wasn't any more room in her heart for romance like that.
Shortly after, Sans had just stopped searching. He'd come to terms with the fact that, perhaps the universe had just made another mistake, an anomaly, and there really wasn't anyone for him.
It hurt him to think about it.
"We've laid another trap for the human over by that blue patch of ice, so take care not to trigger it yourself." Boss snarled, his arms folded as he described the entire new layout to his brother, who had opened his mouth to say something.
"Uh, boss, I can't see blue." It was a simple statement, and the taller skeleton narrowed his eyes before facepalming, groaning out loud about this 'inconvenience'.
"I forgot about your soulmate and their damn freakish eyes. Fine, there is a trap over by the juniper tree about 20 feet that way." Boss pointed with a gloved hand, and Red nodded, seeing it now.
"Alright, I got it. Anything else ya want me to take note of?" He asked, though it was a bit obvious that he was tired and irritable, and only wanted to go home.
"That is all for now. You may return to the house, but only because I know that I'm more than capable of searching the last stretch of the perimeter on my own, you lazybones." Boss rubbed at his bony temple with two fingers, apparently running out of patience for the smaller skeleton.
"Cool, later, boss." Red gave him a wolfish grin, before teleporting away and back to their home, instantly flopping down on the couch without a care in the world.
"Blue, this isn't going to work."
"It'll work, you'll see! We'll just keep hopping from universe to universe until I find them."
"... I hope your theory is correct, 'cause if it's not you know that RP is going to kill us."
"Don't worry, I know it is. It'll be fine!"
"... Yeah, yeah. It's gonna be fine."