The play ends where it began: with a battle.
When Duncan announces that he intends the kingdom to pass to his son MalcolmMacbeth appears frustrated. Even when the entire world is against him he holds his head high with pride. His boldness and impression of personal invincibility mark him out for a tragic fall. She is loving, yet very determined that her husband will be king.
Read an in-depth analysis of The Three Witches. The scene in her castle provides our only glimpse of a domestic realm other than that of Macbeth and Lady Macbeth. When Macduff flees the realm of Scotland for England to conspire with Malcolm against Macbeth, Macbeth resorts to the most cowardly and ruthless of ways to punish Macduff for his insolence.
Macbeth is a brave soldier and a powerful man, but he is not a virtuous one. Hero and villain. He is now frail and quite paranoid just after the murder, this contrasts with him being confident and brave on the battlefield; killing then seemed normal to him, but murder, he feels that he has condemned his soul.
It is however the changes her character goes through that classifes her as marginalised.
In the previous scene, Macbeth has sent his assassins towards his chamber in order to belay his orders, Lady Macbeth could not possibly be present there as well as she has exited further outwards of the castle in the events prior.