At the beginning of the story, Louise is crying in her room because she misses her husband until she realizes she actually doesn't. This is situational irony because the audience expects her to be sad but, she is actually happy. It says "if it were or were not a monstrous joy that held her".
At the end the of the story, while Louise is on the stairs, someone opens the front door and everyone is surprised to see Brently Mallard enter, as he was suspected to be dead. "It was Brently Mallard who entered".
Brently Mallard is a very important and wealthy man. He is an antagonist because he is the main conflict for the protagonist, Louise. He is a very controlling person as described by Louise.Louise thinks to herself "There would be no powerful will bending hers".