At first, when they were making charcoal, they just talked so it didn't make them sleepy. However, the busy master gradually became unable to take the time to make charcoal, and gradually began to hand over charcoal making to Tou.
And at one point, it was completely left to the Master to make charcoal. Since this was his first job, Tou only drank water and made charcoal without sleeping. And when Tou showed the finished charcoal to his Master, they laughed.
"You can only make charcoal, but when it comes to charcoal, you can easily surpass me. This is the first time I've cried. And the first two letters of my teacher's name are mine. I understand. I left my name because your name has been discarded. But I'm proud under the name Tou. I couldn't do it when I was told that Master is a royal family." (Tou)
"The first two letters are… maybe that Master…" (Rei)