Kamado Tanjiro joined the Demon Slayer Corps after his younger sister Nezuko was transformed into a demon. During his formative years, Tanjiro fought numerous demons alongside his comrades Agatsuma Zenitsu and Hashibira Inosuke. His journey led him to battle against the highest-ranking swordsmen of the Demon Slayer Corps – the Pillars – including Flame Pillar Rengoku Kyojuro on the Infinity Train, Sound Pillar Uzui Tengen at the Brothel Town, as well as Mist Pillar Tokito Muichiro and Love Pillar Kanroji Mitsuri at the Blacksmith Village. While the members of the Demon Slayer Corps and the Pillars were undergoing special training in preparation for the upcoming battle against the demons, Kibutsuji Muzan appeared at the Ubuyashiki Mansion. When the leader of the Demon Slayer Corps was in danger, Tanjiro and the Pillars returned to headquarters. However, Muzan unexpectedly led the entire Demon Slayer Corps to the demons' final stronghold, the Infinity Castle, initiating the final battle between the two sides.