Tsuchigomori

Tsuchigomori (土籠) is a teacher at Kamome Academy. He is secretly a supernatural representing the academy's 5th School Mystery, the 4PM Bookstacks, and also its curator.

Appearance
Tsuchigomori is a tall, lanky man. He has spiky black hair, with a long white fringe, and purple eyes. He has unnaturally sharp features for a human, such as claw-like hand and shark-like teeth.

He wears a cream-colored coat with a fuschia sweater and a golden eyeglasses.

In 1969, he is shown to have all-black hair and doesn't wear glasses, his sweater are also replaced with a dress shirt.

Personality
Tsuchigomori is a mischievous and quite short-tempered man. When he's in disguise, he's more calm and caring than when he is in his true form. Although he is a teacher, he is shown to be disliking children because of their noisy attitude. He also likes to joke around, he once jokes about liking to eat human children to Hanako, but only receiving a terrified looks from Hanako, Nene, and Kou.

He also once said that he only pretend to care about his student. Despite what he said, he actually cares genuinely for them. Like how he asked Yashiro Nene about how's the number seven "Hanako"'s doing and how's his and her relationships doing. Nene responds with how Hanako always protects her and that she view him as a friend, which Tsuchigomori replies as a relieve.

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

Now with Hanako as the School Mystery Number 7, Hanako has command over the School Mysteries as a leader. They have a friendly relationship due to their shared past, though Hanako can intimidate Tsuchigomori into following his orders.

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. Kou refers to him as "Spider-face", which Tsuchigomori seems to be annoyed by.

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 regularil interacting with each other in contrast to the rest of the seven school mysteries who keep to themselves.

Trivia

 * His favorite snack is bekko candy.
 * His latest concern is how hard it is to live a double life as a teacher and a supernatural.