In “Much Ado About Nothing,” the villainous brother of Don Pedro is Don John. He is described as Don Pedro’s illegitimate or bastard brother and serves as the play’s principal antagonist.
Don John resents his brother and has recently rebelled against him before the action begins. Although Don Pedro allows him to remain in his company, Don John is openly bitter and determined to cause trouble. His followers Borachio and Conrade help him carry out his schemes.
His most damaging plot targets Claudio and Hero. Don John first encourages Claudio to believe that Don Pedro is courting Hero for himself. Later, he stages evidence that appears to show Hero being unfaithful, causing Claudio and Don Pedro to condemn her publicly at the wedding.
The name is easy to confuse with Don Pedro, who is the prince and Don John’s brother, or with Claudio and Benedick, who are Don Pedro’s companions. Don John’s deception is eventually exposed when the Watch overhears Borachio discussing the plot, leading to Don John’s capture.