Long before the rise of Tanjiro Kamado, before Muzan's terror spread like wildfire across the nation, there existed a generation of warriors whose strength carved the foundation of the Demon Slayer Corps. The Sengoku Era—a time of relentless bloodshed, unshakable honor, and unbreakable will—gave rise to the first Hashira. Among them stood legends like Yoriichi Tsugikuni, the bearer of the Sun Breathing, and his brother Michikatsu, who would later become the feared Kokushibo. Alongside them fought heroes lost to history: the Mountain Bell, the Typhoon Fang, and the Silver Flash of Thunder. This is their story. The beginning of everything.
Long ago, during the chaos of the Sengoku Era—when war, disease, and famine gripped the land—a frail man clung to the edges of life. His name was Kibutsuji Muzan, a name once whispered in pity by healers and nobles alike.
Cursed with a mysterious illness that left his body weak and decaying, Muzan was told he would not live past his twenties. Writhing in fear and rage, he turned to forbidden arts and obscure physicians, searching not for comfort, but for an escape from death.
One doctor offered him a strange remedy—an experimental treatment brewed from rare ingredients and infused with ancient blood techniques. Muzan consumed it with desperation. At first, nothing changed. Then, the fever came.
He lost consciousness for days, teetering between life and death. But when he awoke, the sickness was gone. His body pulsed with newfound strength. His senses sharpened. His heart beat like a war drum.
But with that life came a hunger.
A hunger for blood.
Maddened by confusion and driven by instinct, Muzan slaughtered the very man who had saved him. Thus began the path of the first demon—the Crimson Curse born into the world.
And with it, a new darkness.