The Phantom was the main antagonist in the Phantom of the Opera. However, he evolves into the protagonist toward the end of the musical and revives his role as the protagonist in Love Never Dies.
Erik, commonly known as the Phantom, Opera Ghost, and the Angel of Music in his later life, was born into a small family. We do not know much about his father but we discover that his mother was unappreciative of her son from the moment he was born.
"This face which earned a mother's fear and loathing. A mask, my first unfeeling scrap of clothing."
Erik was bought and used by a travelling circus as an amusement attraction. Known as the Devil's Child, he was beaten and scoffed at by his handlers and onlookers and began to harbor a hate for the human race, particularly those who went out of their way to make fun of him.
In an unexpected twist, Erik overpowers his handlers during a show and strangles him to death. With the help of Madame Giry, at the time a young dancer at the Opera Populaire, he escapes the police and the growing mob and flees to the dormitories of the Opera House. Because Giry wants to make sure no one finds him, she smuggles him into the vaults and underground tunnels which become his home in the coming years.
As Erik grows up in the opera house, he becomes involved with the affairs of the opera.