The Phantom of the Opera is a novel by Gaston Leroux, in which the phantom is a real person, as we discover after getting familiar with the story. The phantom, or Erik, hides behind this made up, terrifying story of being a phantom, just to have some influence in his environment as he avoids normal contact with people and hides his face behind a mask. Even if his presence at the opera is only suggested to the majority of people (he does not appear in person), things change after he meets and falls in love with Christine. Hoping that he can keep her, he abducts her and she gets to see his face behind the mask. Two more witnesses can prove the real existence of the phantom, as they see Erik in the flesh: Raoul, Christine’s friend, and the Persian (an old acquaintance of the phantom).
In addition to this, the prologue of the novel stands as a sort of testimony of the narrator who wishes to make the reader believe in the veracity of the story. These lines, wisely placed in the beginning of the novel, set the register in which the story should be read, as every writer has an ideal reader in mind.
"The Opera ghost really existed. He was not, as was long believed, a creature of the imagination of the artists, the superstition of the managers, or a product of the absurd and impressionable brains of the young ladies of the ballet, their mothers, the box-keepers, the
cloak-room attendants or the concierge. Yes, he existed in flesh and blood, although he assumed the complete appearance of a real phantom; that is to say, of a spectral shade.”