To pass Final Selection, one must survive for seven days on Mt. Fujikasane where demons captured by the Demon Slayers have been imprisoned. So begins the battle for survival between the young swordsmen and the demons. Armed with the breathing techniques and stances he'd learned from Sakonji Urokodaki, Tanjirou slashes demon after demon. His two years of training have not gone to waste. But just then, a morphed demon appears out of nowhere.