The boy with a fox mask covering his face challenges Tanjirou to a fight, to which Tanjirou declines, as the stranger is only wielding a wooden sword, while Tanjirou has with him a real sword.
The boy laughs and easily defeats Tanjirou. The boy also tells Tanjirou that he does not fully understand or is able to utilize Urokodaki's breathing techniques properly. Tanjirou was taken aback at the fact that this stranger knew Urokodaki.
After another brief match, the stranger knocks Tanjirou out cold. As the boy walks away, a girl with a floral pattern kimono approaches, and the boy tells her to take care of the rest.
When Tanjirou awakens, he sees the girl and asks her if she had witnessed the fight. He also tells her he wants to be as skillful as the boy. She tells Tanjirou that he is indeed able to master those skills and that she will be there to witness his strength. She introduced her name as Makomo and the boy with the fox mask as Sabito. Tanjirou thought that she was cute.
Makomo helped Tanjirou to correct his sword postures and breathing techniques. When Tanjirou asked why she was willing to teach him, she only replied, "we all really like Urokodaki-san". Tanjirou notes that that was her catch phrase.
Makomo also tells him that Sabito and her are not siblings, and that there are many children that are watching him. She continues to guide him while Sabito continues to defeat him.
Half a year passes, and Sabito finally comes to challenge Tanjirou with a real sword. A determined Tanjirou tells Sabito that he will win and strikes at Sabito before he could react.
Tanjirou's blade cuts Sabito's mask in half to reveal a gentle smiling boy with a scar on his right cheek. Makomo had kept her promise to witness Tanjirou's progress. As she tells Tanjirou to win and triumph against "that person", mist clouds them.
When Tanjirou got to his senses, Sabito was gone, but the large rock was in front of him, split in half, like Sabito's mask.