After his sister's tragic death, Takehito Kurogane's world hit rockbottom. While going out after a month of seclusion without sunlight, a mysterious teenager approached him, whispering of a need to vanquish "demons." This enigmatic encounter, coupled with Takehito's mental struggles and his stirring reawakening of power, thrust him reluctantly into the role of a demon slayer. In a world teeming with darkness and secrets, will Takehito's strength be enough to unveil the truth behind his sister's death, or will the shadows consume him whole as he faces the ultimate test of his resilience?