Blood represents bravery and death. It is a symbol of how hard macbeth struggled and conquered to become ruler. Blood was the sacrifice in tne play macbeth.
A dagger, voices, a ghost, a head, children, kings and possibly witches are Macbeth's hallucinations.
Yes I think justice is served in the end. Not only is Macbeth killed in the end, but also Lady Macbeth died. Remember that she was the one who originally devised the plan to kill King Duncan. She had puppet strings on Macbeth