Tybalt is the nephew of Capulet’s wife, and that family’s chief troublemaker.
An excellent fenceman, he seeks out opportunities to fight, any excuse being good. He is willing to start a fight at his uncle’s feast, being only restrained by the latter’s fury. Instead, he sends Romeo a formal challenge. He despises anyone who speaks of keeping the peace, and when Romeo simply states that he is not a villain, he does not take this for an answer. He does not much care for Mercutio, and is quite willing to fight with him when challenged. He kills Mercutio by stabbing him under Romeo’s arm, and having fled is foolish enough to return to the square, where he ends up in the fight with Romeo where he loses his life. Though we do not see this side of him, the Nurse considers him to be courteous and honest, and the best friend she had.