I Can't Tell You

Nezuko aims a kick at one of the Swamp Demon's copies, but it slips back into its swamp before she connects. Tanjiro recalls Urokodaki's reminder that his sister is no longer fragile and considers trusting her to guard Kazumi and the captured girl. A puddle then opens beneath Tanjiro and drags him into the demon's murky domain, where he finds heaps of belongings taken from past victims.

Two clones taunt him about the thin air and the drag of the water, but Tanjiro counters that his training on Mount Sagiri prepared him for far worse conditions. As the copies dart around him at sharp angles, he stays focused, reads the Opening Thread, and unleashes Water Breathing's Sixth Form, Whirlpool, severing both their necks at once before surfacing.

Above ground, Nezuko trades blows with the last clone, which marvels at her raw power yet notes her attacks are predictable. After it slashes her face, Tanjiro reappears and removes its limbs. Realizing his other selves are dead, the demon hurls insults at his victims, prompting Tanjiro to silence him and demand information about Muzan Kibutsuji, at which the creature suddenly turns fearful.

Tanjiro and Nezuko continue their battle against the Swamp Demon.

Tanjiro enters the swamp and destroys two clones with Water Breathing's Sixth Form, Whirlpool.

The siblings defeat the final clone, and the demon reacts with intense fear when Muzan's name is spoken.

This installment showcases Nezuko's combat capability as a demon and Tanjiro's adaptability underwater. The Swamp Demon's terror at Muzan's name foreshadows the curse Muzan places on those who dare speak it, a thread that pays off in later chapters.