 Tybalt , meanwhile , still incensed that Romeo had sneaked into the Capulet ball , challenges him to a duel . Romeo , now considering Tybalt his kinsman , refuses to fight . Mercutio is offended by Tybalt 's insolence , as well as Romeo 's " vile submission " , and accepts the duel on Romeo 's behalf . Mercutio is fatally wounded when Romeo attempts to break up the fight . Grief @-@ stricken and wracked with guilt , Romeo confronts and slays Tybalt . 
