The play’s full title is The Tragedy of the Duchess of Malfi, and it contains many classic components of a tragedy. For one, all of the central characters die by the play’s end, many of them in a graphic or tragic manner. The play ends in a bloodbath that kills the Cardinal, Bosola, and Ferdinand. By that scene, most of the other characters have already been murdered by one of those three men.
Outside of the pervasive violence, the play is a tragedy because it focuses on the Duchess’s life circumstances, especially the corrupt political system that dictates her bodily freedom and the destruction of her life and family at the hands of her brothers. Part of what makes The Duchess of Malfi a tragedy is therefore the death of the Duchess’s will to live. Right before she is killed, Bosola recites a poem to the Duchess. His lines are bleak and therefore reflective of her circumstances:
Of what is’t fools make such vain keeping?
Sin their conception, their birth weeping;
Their life a general mist of error,
Their death a hideous storm of terror.
At this point in the play, the Duchess no longer cares whether she lives or dies—a feeling that is very much at home in such a tragic play.