Tsuchigomori

Age: 70+
Height: 6' 0"+
Occupation: Teacher (disguise), 5th Mystery Representative
Status: Disconnected (as a supernatural)

Tsuchigomori is a science teacher at Kamome Academy. He is secretly a supernatural, representing and curating the academy's 5th School Wonder, the 4PM Bookstacks. He is also Kou's current homeroom teacher.

While Tsuchigomori seems like a normal, caring and somewhat meek teacher in his human disguise, he is actually sarcastic, mischievous and quite short-tempered. He's also shown to be quite sadistic, having fun with threatening and scaring Nene and Kou ― although he quickly stops after a light warning from Hanako. Although he is a teacher, he is shown to dislike children because of their noisy attitudes. Tsuchigomori also has an odd sense of humor and likes to joke around, such as saying that he likes to eat human children, only to be met with terrified looks in response.

Despite him claiming that he only pretends to care about his students, he has been shown to actually genuinely care about them on various occasions. When asked why he makes his teacher persona so different than his actual personality as a supernatural, he answers that it's simply because he feels like it.

As the curator of the 4PM Bookstacks, he has access to the entire body of knowledge surrounding the school, along with the present, past, and future. He seems to know everything about every student that has ever attended the school. Even after his yorishiro and boundary were broken, his powers still allow him ways to retrieve the books in the library. He mentions that because of his position, it's possible for him to alter the future, but he does not plan to do so because any curator who does will be erased from existence.