An Oath of Mercy || UnderFell Sans x Reader

seven

So quick note: I included the reader/(Y/N) from my Classic Sans x Reader book in this chapter (she's the cat monster) because I thought it'd be a fun little nod to that along with servicing the plot. If you wanna read that book/save it to read later, it's on my profile :)

Anywizzle, enjoy the drama of chapter seven~

"WHY ARE YOU WEARING SANS' CLOTHES?" Papyrus demanded as the two of you stood in front of him. His arms were crossed—in their default state—while he glared down at you—his default look. Sans anxiously glanced at you, a pleading look in his red eyelights.

"I found some gold and paid him for them." You weren't given much to do other than think while you sat in the shed, so in the event Paps asked, you had an excuse prepared. Papyrus didn't look like he believed you but only scoffed.

"WHATEVER. I DON'T CARE." He marched off, calling over his shoulder, "SANS, KEEP THE HUMAN BUSY."

"Where does he go every day?" you asked idly as the skeleton beside you let out a large breath.

"He's a part of the Royal Guard. He's second in command under Undyne." His anxiety wore off as he spoke, returning his tone to its usual deep, calm bass. It was only now that you noticed just how tense he was around his brother.

"Sounds important." You had no idea what any of that meant. All you did know was that Undyne must be even more ruthless than Paps, and you'd never like to meet her.

"Yeah, no shit." He turned to you properly. "Thanks for that."

"Covering for you? We're friends, I've got your back, Red." You bumped his shoulder. His face mimicked his nickname, and you had to wonder why he was so easily flustered. You asked him as much.

"Monsters don't really...court each other. They're kinda just nice-ish while they're fucking, then they go their separate ways."

"So, what, you think I'm being nice so we can sleep together or something?" You laughed, but he just looked at you. Your smile dropped instantly. "No- that's not what I'm- this is so embarrassing." Flowey popped out of your collar.

"You know she's not trying to sleep with you," he chided, rolling his eyes at the skeleton. You swore there was a story there about why they hated each other so much; you'd have to ask when you got a chance.

"I'm just explainin' how our world works, flower. I don't want her to get too fuckin' chummy with me and not realize everyone else is going to think we're fucking." Sans smirked, looking completely unperturbed about this fact.

"This is mortifying." You put your face in your hands. Did he even have the necessary parts to...?

"You gave her your clothes, what else are they going to be thinking?" Flowey scoffed. You really wanted to curl into a ball and disappear.

"You asked for them, fucker," Sans shot back. "Besides, who cares what those fuckers think?" Your self respect. "Here, I got you this." He shoved something into your hands, and you examined it mutely. It was his red collar, aesthetic spikes and all.

"Why would she wear that?" Flowey looked down at it for a moment, disgusted.

"You're a strategyer- strategyest- someone that can plan. Think about it: monsters don't mess with each other's property. I know those damn dogs yesterday were trying to kill you until you changed their minds or some shit, so this'll help keep you safe when I'm not around to protect ya, sweetheart."

"So you want me to convince them we are sleeping together?" You finally looked at him, torn between looking perplexed or horrified. He grinned, flashing his sharp teeth.