Chapter One: Sorrow and Tears

Demon Progenitor Tanjiro - Tanjiro is deeply ill, the doctor predicted that there was only a month at most until he would have succumbed to the illness. But then after all hope seemed to have been lost; the doctor discovered a new treatment that had been lost to his family for generations. This treatment was brilliant, but he was confused as of why this treatment was lost to history, and why there was only one recorded patient?