_Hamlet_ is Shakespeare's darkest tragedy, no question. Shakespeare continually drops hints about how Hamlet is the one we're supposed to admire (but that's for another thread).

In contrast, Fortinbras is like a sinister presence, continually mentioned but never seen until he walks on stage at the end. His claiming of the Danish throne is supposed to make us feel uncomfortable; it represents a return to the warlike state that existed during old King Hamlet's reign. Actually, I consider Fortinbras more villanous than Claudius; Claudius seems to be a good king in that he uses diplomacy rather than warfare (it's Claudius's personal morals that are in question).