Final answer:
Duncan is the character in 'Macbeth' described as an old, gracious, pious, and gentle man, similar to Lady Macbeth's father in his sleep.
Step-by-step explanation:
In Shakespeare's Macbeth, the character described as an old, gracious, pious, and gentle man, who bears resemblance to Lady Macbeth's father in his sleep, is Duncan. Lady Macbeth makes reference to this resemblance in Act II, Scene II when contemplating the murder of Duncan. She admits that she would have killed Duncan herself had he not looked like her father as he slept, illustrating her disturbed state and the complexity of her emotions toward the act they are about to commit.