Mercutio can be seen as a foil to Romeo because his personality contrasts with Romeo's, thus emphasizing Romeo's traits. At which point in Passage 1 is this best illustrated? when Romeo comforts Mercutio after he has been wounded when Romeo takes revenge for the death of Mercutio by killing Tybalt when Mercutio calls for a plague on the houses of Montague and Capulet when Mercutio insists on fighting Tybalt while Romeo wants to walk away