Undertale One-Shots x Reader (DISCONTINUED)

Gray (Underswap! Napstaton [also testing out the SoulMate! idea])

So I've read in other people's works about the SoulMate! AUs. This isn't an AU like Swap or Fell, but it's saying that there is something that helps you find your soulmate, basically. I decided to try it out for myself with the unoriginal idea that you see in black and white until you meet your soulmate in person. I hope y'all enjoy. Tell me if you think I did it right. And requestor, I'm sorry if it's not what you were hoping for.

"-and then there's green, which is the color most everything in nature is. Plants are green, and there are so many different kinds of green. But flowers, those can be a whole variety of colors, like purple and blue and red. I love how-" Your good friend Alphys was describing the various colors in the world. She had met her soulmate Undyne a long time ago, but still got excited over colors. You could understand. When you grow up seeing only gray shades, colors will never be boring. At least, you assumed. You had yet to meet your soulmate. You didn't know if you ever would.
"Sorry. I started rambling again, didn't I? I'm bumming you out so much. I do this all the time." Alphys had noticed your downturned face and realized what she had been doing.
"It's fine, Al. You don't have to-" You were interrupted by her ringing phone. Alphys squealed happily when she looked at it, which instantly told you who was calling.
"Hey, Undyne, what're you up to?" Alphys had regained her "tough-girl" act. You knew she always wanted to seem strong around Undyne, like no one could ever beat her.
"Uh, you sure? Isn't he still going to be there? I mean, he can be kind of-" The ruse had disintegrated into concern, and her worry spread to you.
Finish your sentence, Alphys! He can be kind of what?! Dangerous? Deadly? What??? Who is he? You were screeching at your friend in your head. 
"Okay, if you say so. Love you too." Alphys hung up her phone and looked at you.
"Want to finally meet Undyne? You don't get a say in this, so hurry up. We leave in two minutes. There's also that robot guy Undyne built, Napstaton. He's supposed to be on the charger, whatever that means. He's... You'll figure it out yourself." FINISH YOUR SENTENCES, ALPHYS! You just wanted to know what he was.
~heyo it's your good buddy the time skipper of boring moments~
The two of you approached a lab that you had seen from a distance many times. Alphys knocked on the large steel door, and a tall fish-woman in a lab coat answered. Alphys instantly scooped her into a large hug and twirled her in a circle. This was clearly Undyne.
"You must be (y/n). I've heard a lot about you!" Undyne was laughing as Alphys put her down, no sign of the "cute stutter" Al always talked about. She shook your hand, then led you both inside. You sat down on a couch, where Undyne had an anime playing. Alphys clapped happily and sat down next to you, pulling Undyne into her lap. Both started to blush profusely. Throughout the show, they would give each other a peck on the lips, which soon changed into long kisses, and in turn became a long make out session. You rolled your eyes and left the couch, searching around for something to erase the upstairs image from your brain. You had your head stuck in a fridge, and you finally decided upon just a bottle of water. You shut the fridge and turned only to run into a tall robot. The world flashed brightly for a moment, and once your eyes had focused, you realized that there was more than just gray.
"Woah. This is... So cool." His voice sounded less like it was created and more like it was echoing inside the metal body. Even still, you couldn't help but melt while listening to it.
"Hi, I'm Napstaton. Like on TV? Have you heard of me?" He sounded hopeful as he helped you to your feet.
"I'm (y/n), and actually, I have. I've always liked your show. Alphys doesn't, really. But I do." A grin spread across his face. He was so genuinely happy to meet you. But you could say the same for yourself. You didn't think you could smile any wider. He was your soulmate! He had on a hat and hoodie that were the same calming color as his eyes, which you were lost in. He still had a hold on your hands, and it seemed he had no intent to ever let you go.
"Your eyes are beautiful, (y/n). Everything about you is." He dropped one of your hands to brush his palm against your cheek. You blushed and leaned your face into his cupped hand.
"NAPSTA! What are you doing?" Undyne and Alphys must have finished eating each other's faces, because here they came rushing into the room. Undyne did not seem happy that her creation had come out of hiding. 
"I told you not to leave! What if something had happened to you? Did you disconnect yourself from the charger? Did you break anything?" Undyne was frantically searching over Napstaton, checking various statistics on a nearby monitor as well. Alphys gestured you over, which took you a little bit to notice. You couldn't help but look at Napstaton. He seemed so... perfect. Once you saw Alphys's frantic arm flailing, however, you snapped out of your love-induced state and followed her out of the room, water bottle long forgotten on the floor. You couldn't resist looking around the now colorful laboratory, and didn't know Alphys had stopped until you ran into her.
"He's your soulmate, isn't he? That's why you're so spaced out." Alphys seemed like a disapproving parent as she crossed her arms.
"There's just so much to take in, Al! It's everywhere! What color is this? What color am I? What color is he?" You sounded like inquiring Undyne, who was still frantically asking questions in the other room.
"I'll tell you all of that stuff later. I just can't believe that your soulmate is Napstaton. He's so... overbearing, I guess. If that's the right word for it."
"Alphys, he is not overbearing! He's one of the nicest guys I've ever met!" You couldn't believe she thought he would be bossy and dictatorial.
"(y/n), you've only known him for a few minutes. You have no idea what he can be like!" Alphys was increasingly getting angrier, and you could feel your blood boiling as well.
"He's rude and egotistical! I think-" Alphys never got to finish her sentence.
"I DON'T CARE WHAT YOU THINK, HE'S MY SOULMATE!" You had completely lost your temper.
"I may have only known him for a short amount of time, but I know that I care about him, and that he cares about me!" You were practically seeing red. You had never been this angry before.
"I do more than care about you, (y/n). I know I already love you." You turned to see your soulmate standing in the doorway. Hiding behind Napstaton's tall form was a saddened Undyne. It was almost as if Alphys and Undyne didn't think you two belonged with each other. You felt your fury dissipating, and tears started to stream down your face. You ran into Napstaton, who instantly wrapped his arms around you.
"Look, I know you don't like me, Alphys. And I know you don't want me to leave you, Undyne. But I know (y/n) is someone who will help make me a better person. Please let us be together." Alphys scoffed at his desperation, but Undyne seemed to look understanding.
"I-I think they should, Al. I-In fact, w-what if t-they l-live together in y-your house? T-Then y-you could l-live h-here with m-me." Undyne had a bright blush on her face. You hadn't ever seen someone do that before, since blush is near impossible to see in grayscale. Alphys seemed shocked at Undyne's idea. She turned to face you and Napstaton after hesitating.
"Don't break my house, okay?" You were so happy that they were going to let you two be together. You may have just met, but you already trusted Napstaton with your life. Undyne and Alphys clearly thought you two would be okay together, if they were going to allow you to live with each other. This would be a good way to get to know each other.
-what's this? the future? okay not like waaaay into the future, just until y'all could get your feet under you-
Alphys had officially moved in with Undyne, and Napstaton was with you. Undyne had made a small book to help you two learn assorted colors, and you were so happy that you could sit in your soulmate's embrace and flip through the rainbowed pages. Of course, the two of you had instantly torn out one of the pages. Sitting in the trash can was the page titled "Various Shades of Gray".