What role does Malvolio serve in Twelfth Night?

Let us remember that Malvolio is at the heart of one of
the central conflicts in the play. Twelfth Night was actually an important festival in
Elizabethan times, that celebrated one last final raucous celebration of excess before
the Christmas season was over and long, dark and difficult January began. In this play,
the party spirit is represented by Sir Toby Belch, whose antics and desire to celebrated
is matched by the dour and serious demeanour of Malvolio, who represents Puritan
sacrifice in all of its black and white seriousness. Consider their confrontation in Act
II scene 3, when Malvolio is awakened by the noise that Sir Toby and his cronies are
making. Sir Toby delivers a very important line in this
scene:

Dost
thou think, because thou art virtuous, there shall be no more cakes and
ale?

The supposed virtue of
Malvolio is matched against the die-hard party spirit of Sir Toby, which of course leads
to Maria's stratagem to make Malvolio look ridiculous.

This
leads us to the second function of Malvolio. The way he is made to believe that his
mistress is in love with him is one of the most hilarious elements of the play.
Malvolio's self-love and his arrogance in showing himself so easily persuaded that
Olivia is in love with him shows the dangers of ambition and of thinking ourselves to be
more than we are.

Lastly, I would also argue that the
character of Malvolio is important in the way that his presence strikes a discordant
note in this otherwise light-hearted comedy. There is a sense in which Act IV scene 2,
in which Feste plays with Malvolio as he is locked up, presents a punishment that is
more than is deserved. Making Malvolio doubt his own sanity is pitiful and makes us feel
sympathy for him, in spite of his many sins. Malvolio's final line in the final scene of
the play, "I'll be revenged on the whole pack of you!", should make us question if this
really is a comedy, and if it is, at what price the humour has been
bought.