A tragic hero must possess some tragic flaw, a negative trait (like pride or ambition) that eventually leads to his hamartia—his error in judgment—which leads to the peripeteia, or reversal of fortune. Finally, the tragic hero endures some punishment (nemesis) for his error, usually his total ruin, and then the audience experiences catharsis, the purging of our intense emotions as a result of the hero's downfall.

Prince Prospero does check all of these boxes. His tragic flaw is his pride, or hubris, which is very common among tragic heroes. Prospero believes that he, with his riches and resources, can escape death, and he abandons his kingdom and subjects, leaving them to their ghastly fate, quarantining himself and a thousand of his most fun courtiers in a secluded abbey. This decision is his hamartia. While there, Prospero throws a huge masquerade party, and the Red Death actually comes, despite all the precautions Prospero and his friends had taken to protect themselves. When Prospero sees the masked figure, he experiences a reversal of fortune—he had always thought himself to be immune from death and disease, but now it has found him—and then he dies, reaping the punishment for his pride. The suspense now over, the reader experiences catharsis as all of the courtiers die too.