No, Carlotta, flamboyan diva of The Phantom of the Opera, is not "real" villain of the piece.
In the 1986 musical, Carlotta is middle-aged, sometimes fat woman, who is replaced by young, thin woman, object of Phantom´s lust. (Problem, of course, is not Phantom´s normal biological interest, but his violent, bullying behaviour.) He attacks Carlotta physically by dropping piece of scenery over her, campaign of dirty tricks which have continued for three years! When Carlotta walks away, Christine steps in to fill the role, but when Carlotta wants - and gets - her job back, she gets impression that Christine is in cahoots with her bully, thanks to Phantom´s notes. She calls Christine "toad", and this causes yet another dirty trick - Phantom sabotaging Carlotta´s performance.
And audiences of the musical - and it´s sumptuous movie version - often blame Carlotta.
Il Fantasma de´ll Opera (1998), written by Gerard Brach (Dance of the Vampires, Repulsion) and the director Dario Argento, crystallizes the Carlotta problem. Set in Paris, the film´s trappings are elegant - Christine´s dressing-room is gorgeous yet cozy place, her costumes are sumptuous, etc. Characters, however, are sleazy; Raoul mistreats prostitute in brothel, Phantom is filthy Manosphere pervert who likes bestiality and bullying fat middle-aged women like Carlotta.
No wonder he lives in the sewers!