Montresor's toast to Fortunato's long life: dramatic irony because Fortunato's life would be taken that night.
Fortunato's toast to the dead: dramatic irony because, as readers, we knew Fortunato was going to die.
Montresor's "concern" over the cold, damp night and Fortunato's health: situational irony because we didn't expect Montresor to feel "concerned" for the man he wants to desperately murder.
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Fortunato's masquerade of a jester: situational irony because he was supposed to enjoy the night lively and laughing but instead he was met with death.
Fortunato's name: dramatic irony because Fortunato sounds like "fortune" and this man is nowhere near luck.
Montresor's "concern" over the cold, damp night and Fortunato's health: situational irony because we didn't expect Montresor to feel "concerned" for the person he's desperately trying to murder.