Which of Montresors character traits affects his reliability in The Cask of the Amontillado?

Montresor's vengeful and manipulative character traits affect his reliability in "The Cask of Amontillado." His desire to seek revenge on Fortunato clouds his judgment and makes him an unreliable narrator as he recounts the events leading up to Fortunato's entrapment and murder. His deceitful and cunning nature further undermines his credibility, casting doubt on the truthfulness of his account.