Maria, Olivia's lady-in-waiting, first serves as "a balancing character" who points out in Act I the drunkenness of Sir Toby and introduces "the foolish knight," his vulgar friend Sir Andrew Aguecheek, as well as Feste, the clown. Her humorous exchanges with Feste contribute greatly to the comedy of Twelfth Night. For instance, in Act I, Scene 5, she succeeds in better punning than the clown. He uses colours to mean homonym, collars, but Maria switches its meaning to the meaning of colours, the flags of different countries.
CLOWN: Let her [Olivia] hang me: he that is well hanged in this world needs to fear no colours.
MARIA: Make that good.
CLOWN: He shall see none to fear.
MARIA: A good lenten answer: I can tell thee where that saying was born, of, ‘I fear no colours.
CLOWN: Where, good Mistress Mary?
MARIA: In the wars; and that may you be bold to say in your foolery. (1.5.4-11)
More importantly, with part of what Harold Bloom calls the "erotic lunancy" of Twelfth Night lying in the "seriocomic rivalry" of Shakespeare and Ben Johnson, whose comedy of humors Shakespeare satirizes, Maria is the character, who with great wit and cunning, orchestrates the practical joke upon the Johnsonian personnage of Malvolio. In contrast to Sir Toby, Olivia's uncle, and Sir Andrew Aguecheeck, Maria appears charming, witty, clever, fearless, and highly intelligent. Clearly, she is a foil to the bumbling Sir Toby and Sir Andrew and the crass and sanctimonious Puritan, Malvolio.
Further, Maria's character also contrasts darkly with the practical jokers and, most especially with that of Malvolio. For, it is extremely ironic that Malvolio, whose name means "ill-will," is not the most malevolent of characters. Truly, it is Maria, albeit a natural comic, who harbors a malice in her heart and is the one truly mean-spirited character in the play. For, in Act III, Scene 4, Maria suggests even that Malvolio is evil, "Lo, how hollow the fiend speaks within him!" (3.4.86), and in contrast to Sir Toby who worries about harming Malvolio, she coolly considers if her manipulations of Malvolio will drive him mad and decides that things will be better without him:
SIR TOBY: His very genius hath taken the infection of the device man.
MARIA:Nay, pursue him now; lest the device take air and
FABIAN:Why, we shall make him mad indeed.
MARIA:The house will be the quieter. (3.4.124-126)
A most clever and multi-sided character, Maria is the one character who befits the satiric and "topsy-turvy spirit" that drives the comedy, Twelfth Night.