There is a tension between the heroic and loyal aspect of his character and the ambition. This results in him questioning his actions repeatedly, but ultimately succumbing to his darker desires
Cruel: he murders his best friend, Banquo, and the wife and children of Macduff
Paranoid: he begins to suspect even innocent people are threats to his power, and even stops sharing things with Lady Macbeth ("full of scorpions is my mind")
Guilty: his hallucinations represent his increasing feelings of guilt for the regicide and murder of Banquo
Masculine: he becomes the cruel, violent man that Lady Macbeth accuses him of not being, and becomes the dominant force in their relationship
Nihilistic: ultimately, he questions the pointlessness of life. For a Christian, Jacobean audience, this would be seen as disturbing