Othello becomes overwhelmingly jealous due to the rumors Iago is telling him about Desdemona cheating on him. (3.3 150-169).
Ate
Othello's "reverse of fortunes" occurs when he finds Cassio and Bianca with the handkerchief that he gave to Desdemona/ This leads him to believe Desdemona gave it to him, and he becomes very angry. (4.1 178-181)
Anagnorisis
I trusted Iago, how could he do this???
Othello decides and tells Iago that he plans on killing Desdemona for having an "affair" with Cassio. (4.1 156-165)
Nemesis
At night, when Desdemona is calling to Othello for bed, he did something that would destroy him and killed his wife by smothering her with a pillow. (5.2 98-105)
Othello finds out the truth about Iago and how he has been manipulating him to ruin his marriage when talking to Emilia. (5.2 185-195)
Othello's fate at the end of the story is killing himself to be with Desdemona, as well as realizing the horrible person he had become.