At the end of the story, Brently Mallard walked in alive and well, as told in the quote "He had far from the scene of the accident, and had not even known there had been one." This is an example of situational irony.
Towards the middle of the story, it was revealed that Louise was actually happy that her husband had died as revealed in the quote "She did not stop to ask if it were or were not a monstrous joy that held her." This is described as dramatic irony.
Louise is the main character. She can be classified as a protagonist and a flat character. It is assumed that she married Brently Mallard for his wealth. She is greedy and self-centered. She is very unhappy with her marriage and only loved Brently occasionally. She has dreams of traveling and being free, but is not able to fulfill these wishes. She is overjoyed that she could finally "live for herself," at the news of Brently's death.