When frisk decided to leave the underground after freeing all the monsters, she comes back 4 years later to find out everything has changed-not only the whole underground, but the monsters in it, especially one special skeleton to her- Sans..
*This will be my own personal interpretation of how underfell came to be and will be Frisk X Sans shipping, please enjoy! This will be my first official story for me to ever post on the internet! Any constructive criticism is welcomed! I know I do not have the best grammar or spelling so please bear with me ♡ If anyone has any questions feel free to ask :>
*note: Frisk is 19 and Sans in around 22 yrs old, no, this is not pedophilia, just needed to get that straight. Even without that if you look at undertale logically, there is no way that Frisk is a child- look on the google plus Frisk X Sans community for further explanation or ill just copy paste it here (its very long tho :"D)