Mercutio is slain by Tybalt under Romeo's arm (1 death)(Act 3, Scene 1)
Romeo seeks revenge and kills Tybalt (1 death)(Act 3, Scene 1)
In a chain of unfortunate events, Romeo drinks poison and dies before Juliet awakes. Juliet stabs and kills herself with a dagger after finding out that Romeo had died (2 deaths)(Act 5, Scene 3)