Viola / Cesario
Viola is Twelfth Night's gender-bending heroine. The survivor of a ship-wreck that separates her from her twin brother, Viola washes up on shore in Illyria, where she decides to cross-dress as a boy and take a job at Duke Orsino's court. As the boy servant, "Cesario," Viola quickly becomes Orsino's favourite page and is given the task of wooing Olivia on Orsino's behalf. As "Cesario," Viola's a little too good at her job and she finds herself in the middle of a messy love triangle when Olivia falls in love with "Cesario," who can't return the Countess's favours because Viola is in love with the Duke.
So, why does Viola cross-dress as a boy? She says she wants to disguise her identity as a way to buy some time, to figure some stuff out. But why? What's the motivation here? Well, the answer isn't quite clear. On the one hand, we could say that Viola disguises her identity because she's not capable of facing a world without her brother. This would align Viola with the likes of Olivia, who cloisters herself like a nun to mourn the death of her dead brother. On the other hand, Viola's decision to cross-dress is proactive, which makes her defiant and bold, as she willingly faces whatever comes her way.
While we're asking questions, let's talk about why Viola falls in love with Duke Orsino, because it's a bit baffling. Some critics argue that there's really no good reason for Viola to love Orsino – a guy who is self-absorbed, moody, and obnoxious. This, they argue, makes Viola just as silly as all the other characters that fall for inappropriate partners (Olivia, Malvolio, and so on).
Another answer to this question is that Viola falls for Orsino because he's passionate and poetic. Whatever the reason, one thing is certain: Viola's love, unlike the passions of other characters in the play, is constant and true. Rather than hop-scotch from one romantic interest to the next, Viola's devotion is rock-steady and perhaps even a bit self-destructive. (Why else would she agree to deliver love letters from the man she loves to another woman?)
Anyway, Viola's love for the Duke is the one thing that seems to pull the guy out of his self-absorbed world and into a relationship with another human being (rather than the relationship he seems to have with himself). Similarly, Viola or "Cesario" is also the magnetic figure that draws Olivia from her cloistered state of "mourning" into the land of the living. Even though Olivia doesn't wind up with "Cesario," she does transfer her desire from "Cesario" to Sebastian. Without Viola, then, Olivia and Orsino would remain locked into their self-absorbed states.
OK, so what? We're glad you asked. Let's think about the big picture for a moment. As a comedy that works toward the consummation of heterosexual desire, Twelfth Night uses Viola/"Cesario" as the mechanism that throws the world into temporary chaos (her cross-dressing causes most…