The two male comic characters, while considered as a sort of team, represent the opposite sides of a coin. Sir Toby Belch, as his name indicates, is earthy, crude, very fat, and jolly. Sir Andrew Aguecheek, as his name might indicate, is tall, long, thin, and balding.
Sir Toby is also the opposite to Sir Andrew in intellect. Sir Toby is actually a sharp, witty person who, even when he is drunk, is capable of making a good pun or of creating an ingenious and humorous plot complication. For example, he appreciates Maria not for her looks or for romantic matters, but because she is capable of contriving such a good joke against Malvolio. We are not surprised, at the end of the play, when he marries her.
Sir Toby's character is similar to an earlier comic character of Shakespeare's, Sir John Falstaff. Both characters share many of the same qualities. For example, both of them are given to excessive drinking and eating, both love a good prank, and both enjoy harassing serious-minded people like Malvolio. Thus, while Sir Toby is a knight, he is still a rather corrupt individual. After all, the only reason he keeps Sir Andrew Aguecheek around is to gull him out of his money. The fact that he can tease and play jokes on Sir Andrew is secondary to his primary purpose of using Sir Andrew's money to continue drinking. He is indeed guilty of misusing his niece's house and of abusing her servants; yet in spite of all of his faults, Sir Toby is, perhaps, Shakespeare's most delightful comic creation, after Sir John Falstaff.
Sir Andrew Aguecheek, on the other hand, is merely a foolish fellow who is easily gulled and who does not realize that he has been cheated. It would take a very foolish fellow to think that such a rich and beautiful lady as Olivia would seriously consider this "ague"-looking, skinny, balding, and ugly man as a possible suitor. In addition, he is a coward, and a good deal of the humor surrounding him comes from how he is tricked into fighting with Cesario, and then later, what happens when he encounters Sebastian. Sir Toby sums up this comical knight with the comment: he is "an ass-head, and a coxcomb, and a knave; a thin-faced knave, a gull."
