Erik's Appealing Character (Dramatic Irony)
Erik wishes to be loved for his own sake and accepted for who he is. He does indeed have many good qualities: he is a talented architect and engineer, an excellent musician, a brilliant composer, and he adores Christine and will do anything for her. Yet because he feels rejected and unloved by the world due to the way it reacts to his appearance, he lashes out unpredictably, violently, and sadistically. This unpredictability of behavior causes people to fear and mistrust him. Ironically, it is Erik's conduct, not his face, that causes him to be hated and feared.
A Blameless Killer (Dramatic Irony)
Erik blames everything about his life on other people: he blames other men for turning him into the phantom, and says if he ends up being saved, it'll only be thanks to Christine. Despite his proactive behavior in building the trap-doors into the Opera, constructing a subterranean home for himself, and working out clever ways to make a living, Erik takes no responsibility whatsoever for his actions. In his mind, everything he does is a reaction to a slight visited upon him by someone else; however, in reality he has a habit of killing people.
Carlotta's "Sabotage" (Dramatic Irony)
Carlotta believes she is sabotaging the much more talented Christine, but in reality she is setting herself up as a target for the Phantom's revenge.
Masks (Situational Irony)
Erik bitterly resents the necessity that compels him to literally wear a mask to hide his ugly face; however, ironically, Erik is much less masked than the other, metaphorically masked characters. Christine plays at a bogus engagement with Raoul, both Christine and Raoul try to deceive Erik, and even the Persian sometimes misrepresents himself by lying to Erik about why he has come.
