Through Byakuya’s message to Senku, we learn of the events that started Ishigami Village.
That sure is something a former 
teacher would think of.
.هذا بالفعل شيء لن يفكر فيه إلّا المعلم السابق
Da merkt man, dass du mal Lehrer warst.
On voit que tu étais professeur,
avant.
È da queste cose che si capisce
Eu sei que é uma coisa que 
um antigo professor pensaria.
Вот он, бывший профессор.