Tanjiro encounters Mist Hashira Muichiro Tokito and Kotetsu, a boy from the village, arguing. Muichiro is demanding that a "certain key" be handed over to him from Kotetsu. Being unable to look on in silence, Tanjiro intervenes to speak on behalf of Kotetsu, however Muichiro refuses to listen. According to Kotetsu, the key is used to operate a battle-type Mechanical Doll, Yoriichi Type Zero, that mimics the movement of a certain real-life swordsman...
I saw something shiny
when I glanced toward the bottom of the river...
رأيتُ شيئًا لامعًا عندما نظرت 
...إلى قاع النّهر
Als plötzlich der Grund des Flusses vor mir
auftauchte, war da irgendein Licht zu sehen.
Al mirar al fondo, vi algo que brillaba.
Miré hacia el fondo
y vi algo brillando,
En regardant le fond,
je vis quelque chose briller.
जब मैं नदी के तल में देखा,
Guardando verso il fondo
Eu vi uma coisa brilhante quando 
olhei para o fundo do rio...
А на дне реки внезапно замаячил свет.