Iago? Edmund? Don John?

."..I am sick in displeasure to him,and whatsoever comes athwart his affection ranges evenly with mine."

As a completely misanthropic, unhappy, cruel villain, Don John from Much Ado About Nothing is in the company of Shakespeare's greatest villains.  Like Iago, who attempts to ruin the marriage and lives of Othello and Desdemona (and succeeds brilliantly -- he murders her for adultery, then kills himself when  he finds out she was innocent) he seems to thrive on other people's misery.  When he notes that Claudio has designs to marry Hero, he declares,

if I can cross him any way, I
bless myself every way.

 He tries twice to break up the wedding of Claudio and Hero, and his meddling has the potential to cause a real tragedy.

But he's significantly different from Iago the arch villain in two ways:  First, he doesn't pretend to be everyone's friend in order to get what he wants.  Rather, he is an openly declared villain.  To his friends Conrade and Borachio he is particularly honest:  "Would the cook were a my mind," he tells them after commenting on a feast being prepared.  In other words, he tells his friends he would like to see everyone else poisoned.  There are no secrets with Don John.  Granted, he relies completely on deceit to make his schemes work (through his disguise in Act I and later by setting up Hero) but he is transparent in his intentions.  Here he is in Act I:

I cannot be said to 
be a flattering honest man, it must not be denied 
but I am a plain-dealing villain. I am trusted with 
a muzzle and enfranchised with a clog; therefore I 
have decreed not to sing in my cage. If I had my
mouth, I would bite; if I had my liberty, I would do 
my liking: in the meantime let me be that I am and 
seek not to alter me.

Sydney Herbert as Don John  (1913 New York)
From the Folger Shakespeare Library's
Luna Collection

We learn he has a reason to be angry at the world -- as first world problems go -- since he is the bastard son of Don Pedro, and therefore not eligible to inherit his estate.  He'll always live in comfort (he's part of the family, sort of) but he never will have the authority or power or responsibility that goes along with a legitimate title. He is stuck as an outsider. Like Edmund, the bastard son in King Lear, he deeply resents this position.

We also can look at Don John as an example of what can go wrong when we try to deceive people -- as a contrast to the happy accident that happens between Beatrice and Benedick, and in fact, between Claudio and Hero.  Friends of theirs deceive Beatrice and Benedick, into believing they are loved by the other.  What if one didn't react as hoped?  Friar Francis convinces Hero's friends to pretend she is dead.  If you're familiar with Romeo and Juliet, you know what can go wrong there...

So is Don John really so bad?  Well, yes.  But I'd borrow an idea from Liz Dollimore, who writes at Blogging Shakespeare.com that Don John's villainy serves to show us the scary undertones of the "innocent" characters' actions.  As is the case in many of Shakespeare's comedies, if we think about the reasons for the marriages, we might feel a bit uncomfortable with the way we arrive at the happy ending.  Don John serves to remind us of how the same ploy -- deception -- can bring us to a tragedy.