Because Borges likes to include so many authorial voices (see our discussion about "Narrator Point of View"), he varies his tone according to who's speaking. When our anonymous historian introduces the story, for example, the tone is academic and a bit stuffy. The "manuscript editor" who includes the footnote on page one, on the other hand, is indignant. Yu Tsun's tone, on the other hand, is more melancholy and full of foreboding. He says lots of ominous, uncheerful things, like "with the eyes of a man already dead, I contemplated the fluctuations of the day which would probably be my last." Since he's the narrator we hear from the most, the overall tone is one of gloom and doom.