act 4 scene 1

Although one of his greatest fears regarding Desdemona's alleged infidelity was that it would blacken his name and reputation, the irony is that Othello is doing that himself; in striking Desdemona out of unreasonable cruelty, he besmirches his own good name. His civility ebbs, as he continues to become the cruel, jealous, passion-spurred "savage" that Brabantio accused him of being. He is beginning to become a stereotype by his own doing, as he falls farther and farther from himself.