Perfection is a Promise | (Mobfell! Sans x Reader)

His introduction into your life matches his behaviour: rough and erratic.

You can tell Sans has been keeping an eye on you since the first time he came to hear you sing, but you didn't expect he'd end up coming to you for a favour.

It's a favour that might as well be considered a life-changing mission, with how the results could greatly affect the future of monsters and humans on the Surface.

He insists it's not that big of a deal, but as each day gets increasingly complicated and bigger responsibilities fall on your shoulders, it feels like there's a lot more than meets the eye.

Skip to a couple of months working under his wing, and he confesses his true motivation for having you alongside him since day one.

• • •

NOTICE: This work is based off Sooner or Later, You're Gonna Be Mine.

The major differences from that alternate universe are that Frisk remains unchanged from the original Undertale universe, and the Reader replaces Frisk's role as a singer.