Tsuchigomori Ryujiro

Appearance
Height: about 182 cm (6 feet).
Hair: Spiky black with long white bangs.
Eyes: violet.
In human form, he appears as a tall, thin man.
In his true supernatural form he has:
pointed ears;
clawed hands;
shark-like teeth;
four extra limbs protruding from the lower back.
Clothes: cream coat, fuchsia sweater, gold sunglasses. In 1969, he wore a dress shirt instead of a sweater.
A teacher at Kamome Academy.
The fifth school secret is the keeper of the "Four O'Clock Shelves" in the school library. This place appears at four in the morning, and books with students' names appear on its shelves: they record the stories of their past and future.
The name is a reference to the yokai Tsuchigumo (Earth Spider), with the phonetic element "go" (five) referring to its number as a school secret. Over 70 years old.
Character
rude and hot-tempered;
in the role of a teacher, he is more calm and caring than in his true form;
doesn't like children because of their noisy behavior;
has a strange sense of humor and likes to joke (for example, he says that he likes to eat human children);
sometimes he genuinely cares about his students, despite his outward behavior.
Capabilities
As the curator of the shelves, she has access to the entire body of knowledge related to the school—including the present, past, and future. She knows everything about every student who has ever attended the school. She could change the future, but she doesn't: a curator who breaks the rules will be erased from the face of the earth.

Additional facts:

favorite snack - bekko candies;
hates loud sounds (such as thunder) and cars because of their high speed;
afraid of the cold and doesn’t like snowy weather;
a favorite festival attraction is catching water balloons (yo-yo);
His yorishiro (physical embodiment of the spirit) is a moonstone found by Hanako at four o'clock in the morning.