Soulmate (Underswap Sans x Reader)

Shower of Kisses

It was finally spring break. The last of winter had melted away, and warmth was slowly starting to creep back into the chilled air.

Sans worked as a security guard at Asgore's school, so he was off for spring break too. The two of you had gone with Alphys and Undyne to a nearby park to enjoy the weather. Right now, Sans and Alphys were sparring in the open field, Undyne nervously cheering them both on. You sat at a park bench, unloading a picnic basket.

"Hey punk!" yelled a rough voice. Alphys was walking towards you, a silver battle-axe slung over her shoulder. "Quit sitting around! C'mon, spar with us!"

Alphys and Sans had finished a round of sparring – Sans looked a little out of breath, and they both had a few scrapes on them. Sans still looked at you eagerly.

"YOU SHOULD TRY IT!' He said hopefully, "I'VE NEVER ACTUALLY SEEN YOU FIGHT – BUT I'M SURE YOU'LL BE AMAZING AT IT, Y/N!"

You laughed nervously, standing up to join them. "I dunno', guys, I really don't fight." You said, rubbing your arm. "Besides, I could never beat either of you-"

"DON'T SAY THAT, Y/N!" said Sans, "I'M SURE IF YOU TRAINED, YOU'D BE JUST AS GOOD AS ME AND ALPHYS IN NO TIME!" he paused. "BUT, IF YOU REALLY DON'T WANT TO FIGHT, THAT'S FINE TOO."

You smiled, and squeezed his hand. "Thanks for understanding." You looked over at Undyne, and grinned. "I think I'll join the cheering section though. Me and Undyne can both offer moral support!"

"Y-Yeah!" stuttered Undyne, "F-fighting's not really my thing either."

Alphys' face split into a sharp-toothed grin. She threw her arm around Undyne. "Bwahahaha! Hey Sans, both our girlfriends are total wimps!"

"Hey!" You said indignantly.

"What?" She said, grinning at you. "You're both total wimps with big hearts – that's why we both love you two so much – right Sans?"

"RIGHT!" he said, giving you a boney kiss on the cheek.

You felt yourself blush a bit, and saw Undyne's face had turned as red as her hair.

"O-Oh gosh, Alphys..." Undyne muttered, burying her face in her hands.

"Heh, I love you too, Sans..." you said, smiling and pecking him on the cheek.

"Well, enough lovey-dovey stuff – I'm gonna' kick Sans' butt in this next match!" shouted Alphys.

"ACTUALLY, ALPHYS, I, THE MAGNIFICENT SANS, AM GOING TO KICK YOUR BUTT!" he retorted.

You laughed, and followed them to the sparring ground, falling into step next to Undyne.

The two monsters began another round of fighting, the air crackling with magical energy as they summoned bones and axes. Bullets flew through the air at breakneck speed as the two dodged and weaved around each other's attacks, expertly defending and attacking in turns.

Even though the battle looked intense, you knew neither of them would really hurt each other. You cheered as Sans blocked a particularly powerful volley of axes.

"Whooo! Go Sans!" You cheered. The skeleton's eye lights turned into stars as he snuck a glance at you. His smile widened a bit, and he launched another attack with renewed vigor.

"Y-You got this Alphys!" Undyne cheered, smiling despite her nervousness. "Yeah! T-That's my girlfriend, everyone!"

Sans and Alphys continued sparring for half an hour more, until finally, Sans managed to catch Alphys off-guard. He deflected one of her magical axes with a large bone, hitting the axe right back at her. Alphys stumbled back as it hit her square in the chest, exploding into a burst of magical energy and knocking her to the ground. In a flash, Sans trapped her in a ring of bones, each of them faintly glowing blue.