a time in Scotland when royal succession was a matter of the king hand picking a successor or the eligible nobles fighting to the death until one was left--not very efficient use of noble blood. Duncan decides to pass over Macbeth not because he is unworthy or has questionable loyalty but because Duncan seeks to establish the stabalizing rule of male primogeniture: the crown going to the eldest male descendant. So while Macbeth is a great warrior, a great nobleman, a great military leader, and a great and loyal liege to King Duncan, overriding concerns of greater importance excluded him from succession.

Macbeth reacts, as do his comrades, with normal shock and disappointment and undoubtedly some self-righteous self-congratulatory rage at Duncan's choice but his reaction extends a little further than his comrades because he has dreams of ultimate power. Now his character sketch gets a little tricky. Why does he believe the Witches? Why does he let Lady Macbeth insinuate and insult him into doing what his conscience naturally recoils against? Why does he proceed with the deed even though his conscience, some would say his soul, is crying out against carrying it forward? Does he really want the power or is he motivated by some other more complex psychological reason? Does he go mad and when? Does he have any traits that permit him to be read sympathetically and forgiven? Even Banquo wants to know, "why do you start, and seem to fear / Things that do sound so fair?" (I.iii.51-52).

It may be that Macbeth is superstitious while being a powerful leader and general who is notwithstanding weak willed and full of conceit and vain egoism. These traits would explain why he caves in to the witches and to Lady Macbeth, who manipulates him by assaulting his manly qualities of courage and fortitude. Perhaps his weakness is that he, though a domineering leader of armies, is easily dominated himself and thus incapable of attending to his own conscience even though it speaks to him and recoils against doing the wrong prompted by others. Perhaps this is why the Witches approach him in the first place: they perceive the cowering spirit in him that underlies the greatness on the field of battle. These traits would also provide the complex psychological construct from which he reacts and follows rather than leads as when on the field of battle. In the end, his courage in battle shows itself as calamity reigns down upon his guilt and anger and despair.

When Shakespeare's Macbeth begins, Macbeth is a noble and courageous military leader. He's defeated the King of Norway and the treacherous Macdonwald in a decisive battle, and for his efforts he is fated to earn King Duncan's approval and admiration. Based on the way the play opens, it's easy to view Macbeth as an honorable man, one who could be potentially destined for greatness.

The way that Macbeth's character unravels is what makes him a tragic figure. With the Weird Sisters' prophetic promises ringing in his ears, Macbeth increasingly allows his ambition to get the better of him. At first, though he is clearly tempted by the chance to kill Duncan and steal the crown, Macbeth seems reluctant to follow through with his schemes. However, once Macbeth actually does murder Duncan, he truly begins to change. He becomes increasingly paranoid and resorts to ruthlessness to satisfy his craving for security. Indeed he even goes so far as to murder one of his closest companions, Banquo, and all of Macduff's family. By the end of the play, Macbeth has become a true tyrant, and, when Macduff kills him, Macbeth seems to have recognized the uselessness of his hunger for power and to have embraced despair. For an example of Macbeth's despair, take a look at his famous soliloquy responding to Lady Macbeth's death in Act 5, Scene 5:

Tomorrow, and tomorrow, and tomorrowCreeps in this petty pace from day to dayTo the last syllable of recorded time;And all our yesterdays have lighted foolsThe way to dusty death. Out, out, brief candle!Life's but a walking shadow, a poor playerThat struts and frets his hour upon the stageAnd then is heard no more. It is a taleTold by an idiot, full of sound and fury,Signifying nothing. (21-30)

This soliloquy is a meditation on the apparent uselessness of life, at least according to Macbeth's perspective. Thus, we can see that Macbeth begins the play as a courageous, even heroic figure, but through the course of the narrative he transforms into a paranoid and despairing tyrant. This transformation is truly tragic, and it's impossible to avoid wondering what kind of man Macbeth might have been if he hadn't heard the Weird Sisters' prophecy. 

Macbeth was a soldier and a good friend, it is true.  I would say his greatest trait is that he is easily influenced.  He's fine with his status, and then the witches tell him he will be king, so he wants to be king.  Lady Macbeth tells him to kill Duncan, so he wants to kill Duncan, and then he doesn't want to kill Duncan because he has been nice to him.

Macbeth began the play as a heroic warrior, but the lust for power and weakness in the face of his wife's ambition lead to his downfall. He feels the intense desire to be king, once he is told he will be, but when he tries to get out of the mess he has created he cannot defeat his wife's will.

Macbeth was an honorable warrior, content to be fighting to protect King Duncan and Scotland. After he meets with the witches, he is changed. He begins to dwell on murderous thoughts in order to get the crown. The witches planted seeds in Macbeth, and he begins a murderous campaign to get to the throne. Macbeth either murders or has those in his way murdered. Macbeth is manipulated by his wife. He gives in to her manipulation and control. Macbeth ends up being destroyed because he gives in to temptation.  

Macbeth is a very dynamic character. In the beginning of the play, Macbeth is willing to allow chance (fate) to get him the crown. Soon into the play, Macbeth, driven by his ambition, begins a murderous rampage to gain and keep the throne. At one point, Macbeth does begin to question everything he has done. IN the end, he is destroyed for his actions.

The short answer to this question is that Macbeth is a different character at the end of the play than at the beginning. He is portrayed early in the play as an honorable, brave lord and vassal, who is nevertheless fierce in battle. But his encounter with the witches immediately sparks his ambition, and he begins to contemplate horrible deeds. Yet he is very reluctant to kill Duncan, and shows remorse for it. By the end of the play, however, with several more deaths to his name, he is a murderous villain, unmoved even by news of his formerly beloved wife's death by suicide. His ambition, combined with fate and the supernatural, has destroyed whatever humanity there was in him.

Macbeth is one of Shakespeare's tragic heroes. As with any Shakespeare tragedy, Macbeth starts out as a good guy, a loyal friend to the king and a war hero until he succumbs to his pride and kills in order to become a king. He is manipulated by his wife as she questions his manhood, too. The consequences from these actions cut deep within his soul to destroy him and his marriage. A tragic hero goes from being someone of great worth to someone who is made the fool by following or believing a lie that leads to his/her demise. From Macbeth, the message seems to be that no power is worth having if it requires a person to demoralize himself to the point of doing outrageous and hideous things to other people for his own selfish reasons.

Macbeth can be described in many ways. One way to see his character is as a man overwrought by ambition. In pursuing promotion and power, Macbeth essentially loses his moral core and finds his punishment for this very quickly. 

He is guilty of betrayal and weakness of spirit, each feeding off the other in a cycle of cause and effect.