In Macbeth, do you think Macbeth is a free agent or a victim of fate?
This is an interesting question, since the answer depends on the viewpoint you consider. Macbeth, for example, clearly believes that he is a victim of fate. In Act I, Scene III, for instance, Macbeth talks a lot about fate ("chance") and its role in making him king:
If chance will have me king, why, chance may
Without my stir.
Similarly, when it comes to the murder of King Duncan, Macbeth believes that he is being guided by a dagger, as expressed in his famous dagger soliloquy.
The reader, however, is perhaps more inclined to view Macbeth as a free agent who allows his inner ambition to control the course of his own destiny. Remember that Macbeth is responsible for much of the violence in the play: he kills King Duncan, he orders the murder of Banquo and Fleance, and the family of Macduff. Macbeth is, therefore, in control of his own actions and capable of making his own decisions.
Ultimately, Macbeth is a free agent, but by allowing himself to be influenced by his own ambition and the ambition of his wife, he guarantees his own downfall.