Kimetsu no Yaiba Season 1 Episode 5.
The demon’s body dissolves and the souls of Urokodaki’s students he killed depart to the afterlife. Tanjiro continues to survive, asking the demons who attack him if they know how he can turn Nezuko back into a human, though none answer him. At the end of the Final Selection, Tanjiro and three others return to the wisteria and the twins greet them as the only survivors. The twins tell them there are ten ranks in the Corps and the four are now Mizunoto, the lowest rank. New, stronger color-changing swords will be made for them after they pick the ore, though they will take time to complete. Each are assigned a Kaugai crow to help in communication and given new uniforms. One applicant angrily demands the sword but Tanjiro stops him from harming the twins by nearly breaking his arm. Tanjiro returns to Urokodaki’s and happily finds Nezuko awake after a year and a half long slumber. Urokodaki is relieved he’s alive. He tells Tanjiro Nezuko is likely recovering her strength by sleeping instead of eating humans. 15 days later, Tanjiro’s new sword is delivered to him by Haganezuka, the swordsmith. Tanjiro’s sword changes to black when he draws it, a rare color. A Kaugai crow flies in and tells him he has orders to go to a town to the northwest where young girls have been vanishing and kill the responsible demon, his first assignment as a Demon Hunter.