The word fear occurs forty-eight times in William Shakespeare's Macbeth in noun and verb forms and as a root in words such as afeard and fearful. Which character exhibits the most fear (addressing what causes their fear and how their fear differs from guilt)?
There are numerous characters who exhibit fear in William Shakespeare's Macbeth. Malcolm and Donalbain fear being killed next. Banquo fears the three murders will kill his son. Lady Macbeth fears that Macbeth is not man enough to do what must be done (in murdering Duncan). Although many of the characters show some fear, Macbeth proves to be the most fearful character in the play.
In the beginning, Macbeth "fear[s] things which do sound fair" (I, iii, 54-55). Given the unknown of the witches, Macbeth fears things which he does not understand (both the witches and the prophecies).
Later in the same scene (lines 146-149), Macbeth continues to contemplate the witches and their prophecies.
Whose horrid image doth unfix my hair
And make my seated heart knock at my ribs,
Against the use of nature? Present fears
Are less than horrible imaginings.
Here, Macbeth states that the witches scared him (given his heart "knocked" at his ribs). He also admits that fears one can see are far less frightening than those one cannot see (referring to the disappearing act of the witches).
Once charged with the murder of Duncan by his wife, Macbeth admits to the fear that the murder of Duncan will "revisit" him.
But in these cases
We still have judgment here, that we but teach
Bloody instructions, which being taught return
To plague the inventor. (I, vii, 7-10)
Essentially, Macbeth covertly states his fear of a "plague" (revenge) coming upon him for murdering Duncan.
Many more examples of Macbeth's fear exist, and, through these few examples, one can support that Macbeth is (by far) the most fearful character in the play. His fears, given they appear far before the murder of Duncan, cannot be confused with guilt. Macbeth's guilt ends very quickly after Duncan's murder and does not appear again.