Is he gone and hath nothing?" , which shows the loss of comedic value and more of a serious-like structure .

How does Romeo react to Mercutio’s death? What does this show about his relatonship?

Romeo is distraught at the death of his friend, however loses his morals that Friar Laurence and Juliet instilled in him extremely quickly as he kills Tybalt for revenge. At first, Romeo is sorrowful for Mercutio’s death as although Mercutio may have made fun of Romeo and stood as the comedic figure in his life, he died trying to defend Romeo and his honour. If Romeo had simply dueled Tybalt, Mercutio would’nt’ve needed to fight for him and die - this brings Romeo extreme guilt and sorrow for Mercutio’s death. However, moments after Romeo feels nothing but pure hatred for Tybalt. He knows what it will mean if he kills Tybalt however he still carries our the muder to avenge Tybalt’s death. Romeo’s reaction of rage to Mercutio's death could have been amplified to such an extent due to the fact that he dies yelling "A plague o' both your houses!”, in the sense that Romeo interpretd Mercutio’s dying words of how he wants Tybalt to be plagued or punished, as a duty that Romeo must take upon himself to thank Mercutio. This implies how Romeo is still immature and foolish towards his morals and duties, Romeo blames it on ‘fate’ for him killing Tybalt, however it is likely however due to the deeply instilled structure of the Elizabithean era of the bonds you keep with friendship and family which fuels Romeo’s guilt for Mercutio’s death. 

What does Mercutio’s death imply? Why is he the first to die?

Mercutio’s death was to imply the change in atmosphere of grief and sadness of the death from the joy and lust of Romeo and Juliet’s marriage. As Mercutio was the comedic character, his death signifies the end of comedy and happiness in the play as the tradgedy of more death follows in the second half of the play. Mercutio's final joke is known as ‘dark comedy’, which illustrates the significance of the recent violence and implies the devestation in the future. Mercutio jokingly asks how, "Ask for me tomorrow and you shall find me a grave man.” This dark humour was not common in the Elizabithean era and would have been very memorable as a surprising joke, however Shakespeare was known for his jokes and attutudes that were modern for his life. The significane of a dark pun instead as opposed to a normal or sexual joke that he commonly makes, creates an impact as it is the first in the play. However, due to his death it is also the last dark joke, implying how because it was such a significant joke yet it was also about death, signifies how his death is foreshadowing primarily no more humour as well as future death. Him being the first character to die demonstrates the lightheartedness of the play before, that was mainly from the humour Mercutio brought - his death is so significant ebcause without his humour and the consequence of his death brings about so much negativity that it strongly foreshasows the tradgdy yet to come in the play.