Macbeth is the tragic protagonist of William Shakespeare’s play "Macbeth". He is a Scottish nobleman who is initially portrayed as a brave and loyal soldier, but his ambition and desire for power lead him to commit a series of heinous crimes, including regicide, in order to become king.

Throughout the play, Macbeth’s character undergoes a dramatic transformation. He starts off as a noble and honorable man, but his ambition and the influence of the witches and his wife, Lady Macbeth, cause him to become increasingly paranoid, ruthless, and guilt-ridden.

Macbeth’s tragic flaw is his unchecked ambition, which leads him to make increasingly immoral and violent decisions in order to maintain his power. He is haunted by guilt and hallucinations, and ultimately meets a tragic end when he is killed in battle.

Overall, Macbeth is a complex and multi-dimensional character who embodies the dangers of unchecked ambition and the corrupting influence of power.