Malcolm is functionally one of the most enduring characters of the play as he is introduced to us in the play in Act I, Scene 2 and delivers the very last dialogue of the play when he is hailed as the King of Scotland.
As the older son of King Duncan, he claims primogeniture. He introduces that sergeant to Duncan who conveys the glory of Macbeth and his charismatic victory in the battlefield. He stands out as an obstacle against Macbeth’s belief in the prophecies made by the three witches when King Duncan declares him as the heir to his kingdom.
When he meets Macduff in the court of King Edward, it’s a mark of his character that before trusting him he tests his loyalty to the motherland by demeaning his own self by falsely putting on vices.
In the last scene, he stands in contrast to Macbeth when he delivers his post-victory speech to the ones who stand with him. For some reason, the playwright assigns the final murdering of Macbeth to the character of Macduff although Malcolm is Macbeth’s natural rival. He represents order and his final victory against Macbeth is Shakespeare’s allegiance to the monarchy.
Lady Macduff is the wife of Lord Macduff who is the Thane of Fife. In a play where Lady Macbeth is critically noted for her anti-mother declaration, the presence of Lady Macduff as a fierce mother is significant.
She is one conventionally feminine character in a play full of defiant female presences such as the witches. She harshly criticises her husband saying “he loves us not.” Her short presence is full of such dialogues which prove her blunt personality.
Throughout the play, it’s not clear why Macduff leaves them behind and it is Lady Macbeth who puts up that question. She talks to her son in a pragmatic way after assuming the death of her husband. On the face of death, she fearlessly demeans the murderer by saying how “unsanctified” he is.
The drunken porter is more vividly portrayed than certain secondary males in the play. Harold Bloom claims that with the knocking in the porter scene, the Mind itself knocks and breaks into the play. He imaginatively summons Beelzebub and fancies himself as the porter at the gate of Hell.
He comes with “a healing touch of nature” when we are trying hard to accommodate the unnatural sweep of Macbeth’s lust for power. He invokes Gunpowder plot and in a very indirect way injects in us an air of objective capacity to contrast effects of drunkenness against the wretchedness of Macbeth.