Don John is a character with a uniquely focused moral viewpoint. He has no interest in pretending that his motivations to act against Claudio stem from anything other than pure spite, and he maintains this attitude with a startling clarity throughout the play. As such, he is arguably the most honest character of the bunch, even while he maneuvers and manipulates to bring about chaos, a trait we might find admirable if his actions weren’t so rotten. While Shakespeare’s plays have seen no shortage of wicked figures, Don John still manages to surprise with his calculating shrewdness and generally cold nature. In this way he serves as a foil to his equally calculating brother Don Pedro; while Don Pedro schemes with his friends, joking around and contriving to bring Benedick and Beatrice together, Don John delivers his orders to his underlings in a manner most transactional. Though the consequences of his deceptions bring him joy, his existence is largely an isolated one, absent the camaraderie that characterizes the relationships of his fellows.
The plan to stage Hero’s alleged affair is an audacious one, and speaks to the unrepentant spite that fuels Don John. He has reserved hatred for Claudio solely due to Claudio’s popularity—a popularity that strikes Don John as especially egregious, given his own outsider status and perpetually embittered nature. Not only does he wish to ruin Claudio’s well-being for his own amusement, he also twists the blade further by maintaining the guise of having Claudio’s best interests at heart and, even more reprehensibly, claiming to be a close personal friend.
In spite of a series of actions that might characterize him as merely cruel, jealous of Claudio’s popularity, and bored, there are hints of his plot being fueled by his status as a bastard. Being the illegitimate brother of Don Pedro, Don John does not receive the benefits that his noble-born brother enjoys. Unlike Shakespeare’s many scheming bastards, Don John remains a little more tight-lipped about any bitterness he feels about his position, opting instead of rhapsodize about his evil ways in more general terms. However, he does appear to harbor a certain amount of resentment; at the beginning of the play he has just been defeated in battle by Don Pedro, and in Act 1, scene 3, he claims it “fits [his] blood to be distain’d,” alluding to his illegitimacy and linking it to his villainy. While his less than enviable position does not excuse his behavior, or the cruelness that motivates it, it does shed further light into his interiority. By the play’s end, however, Don John’s actions hardly feel consequential, and indeed his absence while the happy couples celebrate, combined with Benedick’s insistence they “think not on him till tomorrow,” demonstrates his overall insignificance, and how few connections he has in his life.