7 To 22 (Sans X Fem!Reader)
You were a little girl, 7 years old, when you were living with Sans. Actually, the war was going on when you were living with the skele-family. Gaster tried to take care of you guys, but the king needed his assistance. Since Gaster couldn't take care of his own family, Sans took over, taking the father role instead of the brother one.
In your eyes, though, Sans took the responsible big brother role, even though he was 3 years older than you were, making him 10. Papyrus was still a baby bones, but that didn't stop you guys from taking care of each other.
One day, Sans was out with Papyrus, getting groceries, and you where left alone. Who knew that your family would be gone for 15 years and you being left all alone. Until one day, a child named Frisk you knew disappeared and returned with your family.
(Undertale and characters belong to Toby Fox)
(COVER PICTURE IS NOT MINE, IT'S DRAWN BY MY FRIEND)