Answer + Explanation:
In William Shakespeare's play "Romeo and Juliet," it is ultimately Tybalt, a Capulet, who is most responsible for Mercutio's death. In Act III, Scene 1, Tybalt provokes Mercutio into a sword fight, and Romeo, attempting to break up the fight, inadvertently causes Mercutio to be fatally wounded. Tybalt's aggressive behavior and refusal to back down during the altercation ultimately lead to Mercutio's death. While the longstanding feud between the Montagues and Capulets certainly played a role in creating the tense atmosphere that led to the fight, it was Tybalt's actions that directly resulted in Mercutio's tragic end.