Tosanishiki (土佐錦) is a Tosa dog, whose disembodied spirit settled between 2 movable bookshelves at Sankai High’s library.
His breed is Tosa.
When his owner Fumika Honda asked him to find a book for her at Sankai High’s library as she laid dying after getting hit by a truck, his spirit left his body and settled between the 2 movable bookshelves where the novel is, precluding anyone to enter.
His spirit remained in for a month until Rinne and Ageha brought the spirit of his owner to find the book herself and destroy the letter she left inside so she could pass on. Had he remained asleep for too long, his spirit would have never been able to get back.