Lady Macbeth’s development throughout the play
In many ways, Shakespeare’s Lady Macbeth is an ambiguous character. To some, she is the manipulative embodiment of evil. To others, she is a loyal, supportive wife. In any case, her character develops extensively over the course of the play - just like her husband’s.
From the very first moment we meet her (in Act 1, Scene 5), Lady Macbeth is strong-willed and ambitious. She is reading a letter from her husband about the witches’ prophecy, and unlike Macbeth who initially seems doubtful, Lady Macbeth is more than ready to seize power. She seems to know her husband well and already realises that Macbeth is “not without ambition, but without/ The illness should attend it.” (1.5.19-20). She believes he is simply not ruthless enough to aim for the throne, and to her that is a weakness.
Lady Macbeth does not spend time reflecting like her husband does; instead she acts immediately. In her famous “unsex me” soliloquy, she calls upon evil spirits to remove all her feminine (and thereby weak) qualities:
Unsex me here,
And fill me from the crown to the toe top-full
Of direst cruelty! make thick my blood;
Stop up the access and passage to remorse [...]
Come to my woman’s breasts,
And take my milk for gall. ...