What is the importance of Mercutio as a character in the play?
Mercutio is a close friend of Romeo's but has a very different personality. While Romeo loves and dreams and broods, Mercutio talks and jokes. He is very quick-witted and loves to play on words. He is a source of entertainment in the play with his clever use of language. He is also important as he serves as a foil to Romeo, that is to say he helps to highlight Romeo's character through the contrast to his own. However, he and Romeo also share at least one character trait; they both tend to act rashly. With Mercutio this is seen when he gets himself involved in a duel with Tybalt when there was no need for him to do so. In fighting this duel, which leads to his death, he also helps to develop the plot. It is from this moment that the dramatic tension rises, as Romeo then becomes involved and kills Tybalt in revenge. Mercutio, significantly, also curses both the Montagues and Capulets at his death and this curse might be said to be worked out with the final tragedy of the lovers' deaths.
Mercutio is a foil to the character of Romeo in the Shakespearean tragedy of Romeo and Juliet. He is a brash character and mocks Romeo for his love of Rosaline. Mercutio expresses his tempetuous and fiery personality in his soliloquy on Queen Mab. Mercutio loses his temper and becomes "worm's meat," wounded under Romeo's arm in a sword fight against Tybalt, Romeo's new "secret" cousin by marriage to Juliet. Mercutio is escorted off stage to die, which provides the catalyst for Romeo's banishment to Mantua, as Romeo wants revenge, and receives it, for the death of Mercutio by killing Tybalt.
Whereas Mercutio is emotional and angry and responds to the insults Tybalt taunts, Romeo, now secretly married to Juliet and unbeknownest to Tybalt is his cousin, tries to keep the peace ordered by Prince Escalus. When Mercutiot is killed, this attempt at peace is shattered.