Nezuko was originally an ordinary girl born into a poor yet happy family.
The second born of the six Kamado siblings, Nezuko maintained a strong bond with her mother and siblings.
Tragically, however, a demon named Muzan Kibutsuji came to the Kamado household one day and murdered everyone present.
The only survivors of the massacre were Nezuko and her older brother Tanjiro who had been away at the time. Nezuko was only able to survive because Kibutsuji had transformed her into a demon. Unfortunately this meant Nezuko had a strong craving for human blood and initially attacked Tanjiro.