The story for this AU is that Sans was the subject of experiments by the Royal Scientist, Dr. W.D. Gaster. Gaster’s goal was to free monsterkind by extracting Determination from a human SOUL and safely inject it into a monster. After tons of trial and error, Sans was the first test subject to not undergo the process of Amalgamation, which began phase two of Gaster’s plan; Finding a way to hone the powers of said Determination. Through DT, Gaster was able to learn the functions of the SAVE function and how Determination was able to affect magic through way of Undyne. These sessions, however, became less frequent. Sans was left abandoned and in isolation. Sans’ mind began to be filled with thoughts of why he had been left behind, which grew into resentment for Gaster. Sans eventually broke free of the True Lab, starting a massive killing spree in the Underground that was far removed from his original goals.