MacDuff is first introduced, although his presence is previously noted, when he comes to wake Duncan at Macbeth's castle. He jokes with the porter and seems relaxed until he discovers Duncan's body, revealing that "murder hath...stole...the life o' th' building."(II.iii.65-6) The audience sees how affected he is as he reminds the men, as they discuss the "gore," to "look to the lady."(118)He is immediately suspicious of "treasonous malice"(131). The setting then creates a tension of its own for MacDuff because he is noble and forthright and, in seeking to do the right thing is mindful of his surroundings.
It is also notable that the setting is what alerts MacDuff and makes him suspicious "lest our old robes sit easier than our new."(38) He is fully aware of his position and responsibilities and wastes no time in trying to settle the matter. He intends to return to Fife.
MacDuff's family are in Fife but his allegiance to the throne causes him to leave them and go after Malcolm in search of the truth, never expecting that he is exposing his family to danger. The setting in Fife makes him feel that his family is safe. He does enquire after them, aware of danger, especially after sharp criticism by his wife and when he hears of their deaths in "one fell swoop"(IV.iii.218), he is overcome with grief. He vows to avenge their death against "this fiend of Scotland."(232)
Ultimately, MacDuff is also confident on the battlefield and he feels confident that he can overcome Macbeth in this setting - the battlefield. Tension is enhanced for MacDuff as Macbeth reveals his increasing madness. MacDuff, noble to the end, gives Macbeth an opportunity to "yield" and kills him when Macbeth refuses.
MacDuff is once more in a setting that lends itself to his demeanour, where he can honor his King and fulfil his obligations, releasing him from all the tension.