LastBreath!Sans is the version of Sans from the fangame "Undertale Last Breath" by Sultan/ZerJox. He acts similarly to his canon counterpart, but he's a lot more aware of the RESETs, and the 30 Genocide Routes Frisk has done. Dr. W.D. Gaster, the former Royal Scientist, had escaped his eternal prison, and he told Sans about everything the human had done, and about all of the murder they were causing. Sans has vowed that he WILL stop Frisk, until his very last breath.