The tone of The Phantom of the Opera is dark, somber, and melancholy. In Chapter 1, the narrator explains people's reactions to glimpsing the Phantom:
Sensible people, who had heard the story, began by suggesting that one of his assistants must have played a prank on the machinist; but, when a series of curious and inexplicable incidents occurred in quick succession, even the most incredulous began to wonder.
Here, and throughout the story, the narrator speaks straightforwardly. The reader rarely doubts his trustworthiness because he expresses everything so clearly and explores so many different sides of the story. Sometimes he uses the personal pronouns "I" and "we" to refer to his experience in the opera house. For example, in the prologue, the narrator explains the methods he used to research legends surrounding the Phantom. His transparency regarding his research methods—which include exploring the Paris Opera library and interviewing people involved in the Phantom's story—encourages the reader to trust his judgment and buy into the story.
This omniscient narrator permits the narrative spotlight to fall on many characters, even though the focus remains on Christine, Erik, and Raoul. Through extensive research conducted in the 30 years between the Phantom's story and this particular account, the narrator becomes privy to the thoughts, actions, and motives of each character. Because the events of the story are dark, violent, and mysterious, the straightforward way in which he describes each event contributes to the story's dark and somber tone.