Tsuchigomori/Relationships

Background
Tsuchigomori is a supernatural masquerading as a middle school teacher in Kamome Academy. He is Kou's homeroom teacher and teaches biology. His real identity is School Mystery Number 5, the 4PM Bookstacks' curator. He might not have been the original curator for the mystery, as he notes any curator who tampers with future events would be removed. He admits to adopting a human disguise to circulate his own rumor in order to stay on the Near Shore.

He has been teaching at Kamome Gakuen for a long time, even back in 1969. His hair looked different in the past and his public persona was more in-line with his real personality. Then, he was the homeroom teacher of a peculiar student. He did his best to provide guidance to and looked out for the student to no avail. When the student managed to change his own future, it shocked Tsuchigomori deeply and forever changed his yorishiro as a result.

Hanako
Tsuchigomori is one of the supernaturals who had a past history with Hanako. Tsuchigomori has been teaching in Kamome Gakuen since a long time ago, living as a supernatural in the school. He was Hanako's former teacher and seems to care a great deal about him. He was deeply impacted by Hanako's ability to change his pre-determined future, resulting in the No.5's yorishiro being the lunar rock that he received from Hanako.

After Hanako takes on the role as School Mystery Number 7, he effectively gains command over the School Mysteries, including Tsuchigomori, as a leader. They have a friendly relationship due to their shared past, though Hanako can intimidate Tsuchigomori into following his orders.

Yashiro Nene
Nene and Tsuchigomori didn't have a lot of interactions prior to the reveal of his true identity. Being the curator of the 4PM Bookstacks however, he knows about her lifespan and predicted future.

Tsuchigomori seems to care about Nene as a student, and trusts her enough to tell her about his time as Hanako's teacher after she saw glimpses of it through destroying his yorishiro. He tells Nene that it's up to her what she does with the information, and to rely on him when she feels troubled, because after all, he is still her teacher.

Minamoto Kou
Tsuchigomori is Kou's homeroom teacher. Kou was surprised by the reveal of Tsuchigomori being a supernatural disguising as a teacher. Though Tsuchigomori notes it is not uncommon for supernatural beings to adopt disguise to maintain their connection to the Near Shore.

Tsuchigomori seems to be annoyed at Kou at times, due to Kou constantly referring to him as 'Spider-face', and trying to feed him bugs once. Despite this, he still cares for Kou, allowing him to take a peek at Nene's book despite his insistence that it's impossible to change the future that's already written.

Yako
Tsuchigomori and Yako have been shown bickering ever since his introduction as supernatural. He derogatorily calls her 'Stupid Fox' or "echinococcus" while being addressed as 'Emo Spider' as well as getting bitten by her in her fox form.

Despite their constant quarreling, they both are shown regularly interacting with each other in contrast to the rest of the seven school mysteries who keep to themselves.