How does the description of the montresor coat of arms and motto in paragraphs 46-48 contribute to the reader's understanding of montresor's character?

In Edgar Allan Poe's "The Cask of Amontillado," the Montresor family shield contains a foot crushing a serpent.; while the motto on the coat of arms means "do no attack me with freedom." Therefore, both the coat of arms the shield reflect Montresor's need to punish Fortunato for insulting him and his desire for revenge.