Content Warning: Demon Slayer contains illustrations of graphic violence, including blood, murder, dead bodies, and intense fighting sequences. There is also a brief mention of suicide.

Demon Slayer opens as a teenage boy, Tanjiro Kamado, carries his younger sister Nezuko on his back through snow. She is bloody and unconscious, and he vows to save her.

The manga flashes back to a day ago. Tanjiro and his family live in a rural area of Taishō-era Japan. They collect and sell charcoal in the village for their income. Since it is almost the new year, Tanjiro decides to walk to the village to sell charcoal to earn money for a feast, even though the cold, snowy weather is dangerous. His four younger siblings (excluding Nezuko), who are extremely attached to him since their father’s death, want to go with him, but their mother tells them to stay home this time. He says goodbye to his family, including his sister Nezuko, before heading to the village.

In the village, the residents thank Tanjiro for fixing their things every time he visits. Due to his keen sense of smell, he gets roped into solving minor disputes: When people argue over who broke a dish, Tanjiro can smell it and tell that a cat knocked it over.