Kidnapper's Bog Arc

This is the second story arc of the series. It spans chapters 10 through 13 of the manga and is adapted across episodes 6 and 7 of the anime, with the action set in a settlement referred to as Northwest Town.

The arc serves as Tanjiro's first true assignment after passing the Final Selection, showing how a fledgling slayer handles a real case in the field while still searching for clues about his family's killer.

While pursuing the demon responsible for his family's deaths, Tanjiro arrives in a town shaken by the repeated disappearance of teenage girls. He partners with Kazumi, a grieving local whose own fiancee has been taken, and begins tracking the culprit through the night streets.

The enemy turns out to be a shape-shifting demon who can summon portals leading into a private swamp, dragging victims into a space where they cannot escape. Tanjiro fights the creature across these shifting boundaries, eventually cornering and slaying it before it can claim Kazumi's betrothed.

With the swamp demon destroyed, the cycle of abductions ends and the surviving girls are freed. The case marks an early demonstration of Tanjiro's resolve and his growing competence as a member of the Corps.

The arc also reinforces the looming presence of Muzan Kibutsuji, the demon king behind Tanjiro's suffering, who appears only briefly before the story moves on toward the streets of Asakusa.