Winded Butterflies & Scorching Frost (Sanemi x Kanae, Kyojuro x Female Tanjiro)

Two years and a month after the death of her abusive husband Kyogo, widowed woman Shizu Shinazugawa bumps into healthy charcoal merchant Tanjuro Kamado, his wife Kie and their six children, thirteen year old girl Sumiko, eight year old triplets Nezuko, Takeo and Hanako, seven year old boy Shigeru and six year old boy Rokuta, at sunset and they go with the widower to her home, where she introduces them to her seven children Sanemi, Genya, Sumi, Teiko, Hiroshi, Shuya and Koto. While asleep in the home late that night, both families wake up after sensing the demon king's presence outside the house's doors. Tanjuro and Kie sacrifice themselves by choosing to stay behind to fend the demon king off for as long as possible while Genya, Hanako, Hiroshi, Koto, Nezuko, Shizu, Sanemi, Sumiko, Shuya, Sumi, Shigeru, Takeo, Teiko and Rokuta escape unharmed. This results in the couple being captured and later imprisoned in a building and the fourteen people later being found and brought right to the Demon Slayer Corps headquarters for their safety by some demon slayers. Four years later, Nezuko, Takeo and Hanako, all three of who are now twelve, Shigeru, who is now eleven, Rokuta, who is now ten, Sumi and Teiko have recently become demon slayers and Shizu, Hiroshi, Shuya and Koto have all recently become medics living in the Butterfly Mansion while Sumiko and Sanemi, the two of whom are now seventeen, are now powerful swordsmen alongside his lifelong friend and combat partner Masachika Kumeno, having both been recruited by the organization's leader as demon slayers two whole years after being brought to its headquarters alongside Genya, Hanako, Hiroshi, Koto, Nezuko, Shuya, Shizu, Shigeru, Sumi, Takeo, Teiko and Rokuta.