An Oath of Mercy || UnderFell Sans x Reader

ten

You awoke to angry shouting. You rubbed at your eyes as you sat up—wait, were you in a bed? Looking around in surprise, you tried to piece together what happened last night. You were in Sans' bed! Your face flushed red instantly, and for one long moment, you thought that meant the obvious. But then you pulled your mind from the gutter to remember he was being sweet when you were exhausted last night, and your whole body relaxed—well, save for the blush that only got worse when you recognized you didn't actually mind the idea of sleeping with him.

Then you heard more yelling, and in a panic, you tried to shamble towards the door. Without your crutches, however, it was a weird limp walk that felt as awkward as it looked. But it got you across the room, and when you threw the bedroom door open, you spotted the problem immediately.

Sans was yelling at a purple bunny monster with a sunhat on, and she didn't seem to care for his language or venom. She crossed her arms as she argued right back. "...and that human has taken my entire stock of cinabunnies!"

Sans scoffed. "So you're gonna fucking complain she's helping you sell that shit?"

"You're insufferable," the bunny spat.

"That makes two of us, Hoppi."

Hoppi opened her mouth to respond when she spotted you standing in Sans' bedroom, and her jaw dropped as her ears stuck straight out. Her eyes snapped back to the skeleton. "You really are a human fucker." His eyesockets widened as he followed her gaze to you, and shock and embarrassment mixed on his features before rage took control.

"You got a fuckin' problem with that?" He was seething, and even from your spot on the balcony, you could feel the waves of fury rolling off of him. This was getting out of control—well, more so than it was when you first showed up. You hobbled toward the stairs.

"Sans!" you shouted, pulling his attention to you right as you slipped. One second you were about to get a face full of stair, the next you were standing at the bottom of the staircase with Sans' worried eyelights on you.

"Are you ok?" he asked quietly, checking over you quickly. You smiled at him.

"Yeah, sorry. That was embarrassing." You chuckled awkwardly, playing with your sweater sleeves.

"I got ya, sweetheart." He gave you a genuine smile, and you found yourself returning it without thinking. But then it slipped from his face, replaced with an angry growl. So you weren't the only one feeling Hoppi's eyes on you, it seemed.

"You got somethin' to say, rabbit?" he snapped, glaring at the monster. She raised her paws innocently, but her smile was mischievous. He took a threatening step towards her, but you had your hand on his shoulder to keep your balance, so the intimidating effect was nullified. He sighed silently before moving your hand to the wall, then resumed his march towards Hoppi.

"Just seeing what became of the big bad skele," she teased, her smirk obvious from your side of the room. Suddenly she was suspended in the air by bones just like you were when you first met Sans, and a jagged bone was shoved against her throat. Blood trickled down her neck and she gasped, fear washing over her face. "I'm just kidding!" she protested, trying to pull her throat away from the sharp bone.

"This 'bad bad skele' is still fucking deadly, or did you forget?" The room was suddenly chiller, and even with his back to you, you could see Sans' glowing red eye flash with power. It actually made you freeze despite not being the target of his rage. This whole time he could've strung you up just like that, murdered you within a blink of an eye—you were downright lucky.

"I'm sorry, Sans," Hoppi said, sounding both honest and desperate. The bone was still digging into her neck, and her health was dropping by the second. She was slowly turning pale, and her ears seemed to wilt as she kept her begging gaze on him. Then she turned it to you. "Please, human-"