Mercutio is a fictional character in William Shakespeare's tragedy Romeo and Juliet. He is Romeo's close friend and a relative of Prince Escalus and Count Paris, which allows him to move freely between the feuding Montague and Capulet families

. Mercutio is known for his witty, clever, and mercurial personality. He is fun-loving, optimistic, loyal, and often provides comic relief with his sharp humor and puns, including his famous "Queen Mab" speech. Despite his playful nature, he can be cynical about love, contrasting with Romeo's romantic idealism

. In the play, Mercutio encourages Romeo to forget his unrequited love for Rosaline and attend the Capulet party, which leads to Romeo meeting Juliet. Later, when Romeo refuses to fight Tybalt due to his secret marriage to Juliet, Mercutio, offended by Romeo's perceived dishonor, fights Tybalt himself. Mercutio is fatally wounded by Tybalt and dies cursing both the Montague and Capulet houses, saying "A plague o' both your houses!" His death marks a turning point in the play, shifting the tone from light-hearted to tragic and triggering a chain of events leading to the play's tragic conclusion

. In summary, Mercutio is Romeo's witty, loyal friend whose death catalyzes the tragic unfolding of the story in Romeo and Juliet