Romeo came along supposedly trying to stop the fight, but he ends up letting his friend Mercutio die. Then, filled with rage, he made it a personal goal to kill his new in-law kinsman, Tybalt.
Wretched Romeo came along obviously wanting Tybalt to take the first jab so he himself won't be punished. Romeo got what he wants and “tried” to stop the fight and killed Tybalt after