Who is the main antagonist in Shakespeare's "Macbeth"?

In Shakespeare's "Macbeth," the main antagonist is indeed Macbeth himself. Throughout the play, he starts as a noble and valiant soldier, but his encounter with the witches ignites his ambition and leads him down a dark path. Driven by prophecy and a desire for power, he murders King Duncan to seize the throne. This act sets off a chain of events that not only leads to his own moral and psychological demise but also causes chaos and destruction in Scotland.

Macbeth's internal conflict and transformation into a tyrannical ruler make him a complex character. He embodies the themes of ambition, guilt, and the corrupting influence of unchecked power. While Lady Macbeth plays a significant role in instigating his ambition and is a key character in her own right, it is ultimately Macbeth's decisions and actions that propel the tragedy forward. Macduff and Banquo, while important characters in the narrative, serve more as foils and opposition to Macbeth, rather than as antagonists in the sense of embodying the main source of conflict. Thus, Macbeth's character stands as the central figure of antagonism in the play.