Overall assessment of Macbeth's character varies. Some view him as a tragic hero who held every potential for being a good man but was overcome by the evil forces in his world. Others argue that Macbeth completely lacked any moral integrity. Finally, he is viewed most harshly by some who see him as a Satanic figure, in that he knowingly chooses evil and unleashes it upon the world.
Macbeth commits a trio of heinous crimes in the course of the play: the killing of Duncan, the murder of his closest friend, Banquo (and attempted murder of Fleance), and the deliberate slaughter of innocents in the persons of Macduff's wife and child. Given all this, we may tend to forget that prior to his encounter with the weird sisters, Macbeth is a hero, a loyal warrior in service of the legitimate king of Scotland, Duncan.