What was the dreadful voice that the boy heard in Lafcadio Hearn's "The Boy Who Drew Cats"?

“The Boy Who Drew Cats” is the story of a young boy who leaves home, first to study as a priest and then to pursue the vocation of artist. When he arrives in the next village, he enters a large temple. Not realizing why it is deserted, he utilizes its large blank walls to indulge his passion: drawing cats.
After he has filled the walls with cat images, he recalls that the priest in his former temple warned him away from large spaces, and so he enters a cabinet to sleep. During the night, he hears dreadful sounds, which include screaming and fighting. Once everything is calm again, he goes out to find what seems to be a giant dead rat. He realizes that it is actually a goblin in the form of a rat and that his cats have killed it. The screams he heard were the animals fighting. Of course, some people do not believe in goblins or that drawings come to life and would say that he simply heard real, regular-sized animals.