A Secret

Upon reaching the Swordsmith Village, Tanjiro is welcomed by the chief, Tecchin Tecchikawahara, who explains that the smith Hotaru Haganezuka has vanished. Tecchin admits he gave Hotaru the nickname and insists the smith should be forging blades that do not break rather than blaming Tanjiro. He promises a new sword either from Hotaru or another craftsman, then sends Tanjiro to relax in the springs.

On the way, Tanjiro calms an irritated Mitsuri Kanroji by mentioning dinner, sending her hurrying off. At the spring he is startled to find Genya Shinazugawa, but his attempt at friendly conversation ends when Genya strikes him and walks away.

Over dinner, Mitsuri notes that Genya shares a surname with the Wind Hashira, Sanemi, though Sanemi had denied having a brother. She explains her own warm bond with five younger siblings, and the two resolve to befriend Genya in time. When Tanjiro asks why she joined the Demon Slayer Corps, she sheepishly admits she hoped to find a strong husband. As they part, Mitsuri teases the existence of a concealed weapon somewhere in the village capable of boosting his strength. The next day, searching the forest for Hotaru, Tanjiro spots the Mist Hashira, Muichiro Tokito.

This installment, adapted in Episode 45, develops Mitsuri's character and her relationship with Tanjiro while setting up two key threads of the arc: the mysterious secret weapon and the troubled Genya. It also foreshadows the upcoming encounter with Muichiro.