But He Refused: an Undertale story

Sans is a creation of sorts. His original purpose was to be an assistant and in time, kill humans. Nobody expected him to say no, to run, to never look back at that god forsaken lab. No one expected him to fight back.
(Editing. Cover art artist unknown. I DONT OWN IT. Also don't own undertale or any of the characters. I only own Aiden and Aion)