Chapter 1: Demonization

After a long day of selling charcoal to its residents, fourteen year old girl Mika Kamado leaves the nearby town at sunset and goes back up to the top of Mount Kumotori. After getting home, she is greeted by her forty nine year old parents Tanjuro and Kie and five siblings, thirteen year old triplets Nezuko, Takeo and Hanako, twelve year old boy Shigeru and eleven year old boy Rokuta. After finishing their dinner and cleaning up, the family of eight receives a surprise attack from the demon king, who knocks out the siblings and gives his blood to Tanjuro and Kie after killing them. The next morning, the Kamado siblings wake up to learn the exposure to demon blood had turned their parents into demons with a immunity to the sunlight. Late that evening, Mika is separated from her family when the sadistic and cold natured upper moon demon Doma ambushes them and pursues her while they battle. After forcing the upper moon demon to retreat into the night by beating him with her family's sword after half a hour of battling, she is found badly injured from the battle by the blind and animal loving Demon Slayer Corps member Gyomei Himejima, who uses his speed to quickly get her back to his home to treat her wounds after she blacks out from them. Soon afterwards, she ends up falling into a coma due to her injuries and is placed in the care of sisterly pillars Kanae and Shinobu Kocho, both of whom place the younger teen in a hospital bed. After a month and a half, Mika wakes up from her coma to see the sweet natured demon slayer Kyojuro Rengoku sitting in a chair beside the hospital bed.