Prologue

On a decent autumn day, kind hearted single mother Shizu Shinazugawa, who had become a widower two years earlier, and her seven children Sanemi, Genya, Sumi, Teiko, Hiroshi, Shuya and Koto receive a surprise visit outside their house from the demon king a hour and a half before sunrise. The demon king then captures Shizu and teleports away with her. Terrified to have witnessed the capture of their mother, the Shinazugawa siblings leave their home with their belongings tightly secured in bags and a wooden cart. Five years later, Sanemi, now eighteen, his girlfriend of eleven and a half months Kanae Kocho, who is also eighteen and had been forced to retire from being a demon slayer a year earlier, his mission partner Masachika Kumeno, who is older than Sanemi, and Genya, now thirteen, are all sent to the mountaintop home of the Kamado family to defend them from the demon king and get there in time to stop him from killing seven of its eight members, Tanjuro, his wife Kie and five of their six children, thirteen year old triplets Nezuko, Takeo and Hanako, eleven year old boy Shigeru and nine year old boy Rokuta, while Tanjuro & Kie's oldest child Sumiko, who is eighteen just like Sanemi and Kanae are, is away from home. After getting home the following morning, Sumiko opens the front doors to discover the four people in the Kamado family's home with her parents and younger siblings trying to help them move past what had happened the night before. Deeply grateful to them for saving her family's lives, she agrees to go with them to the headquarters of the military organization Sanemi and Masachika are members of.