Demon Slayer : Kimetsu no Yaiba (chapter 09 explanation)

Chapter 09:- Welcome Home 

The chapter begins with Tanjiro returning back to Urokodaki's camp with feelings of regret, after failing to gather information on how to turn Nezuko back into a human.

Sakonji, Nezuko and tanjiro hug each other

He arrives at the base of the camp where he's stunned to see the comatose Nezuko kick down the door and strut outside. He frantically rushes out to her but loses his footing and falls into Nezuko's arms where he begins to cry. As Tanjiro weeps in his sister's arms, Urokodaki comes out and hugs both of the siblings, shedding tears of joy at Tanjiro's arrival.

Hotaru arrives to deliver the blade

Face of Hotaru

Fifteen days pass after Tanjiro's return and an unexpected guest arrives at the camp, a tall man approaches Tanjiro and introduces himself as Hotaru, the swordsmith who forged his katana. Tanjiro invites Hotaru into the home, he explains that the katana he brought was a special nichirin sword, which changes color depending on the wielder, and was eager to see what color Tanjiro's katana would be.

Tanjiro pick his blade

Tanjiro's blade transform to shade of black

Tanjiro grips onto his blade which begins to glow and transform to a shade of black. A moment of silence is shared until Hotaru angrily lashes out at Tanjiro for unintentionally producing a black blade instead of a flaring red blade like he had wished to see.

Tanjiro's crow interrupts the dispute to inform Tanjiro to disembark on his first mission, to resolve the mystery of girls disappearing night after night in a neighboring town.

Girl get disappear