At the beginning of Act III the comedy turns to tragedy. Even the weather has become hot and "the mad blood stirring" (III,i,4). First, Mercutio is slain by Tybalt, and, then Tybalt by Romeo. Ironically, Mercutio, who seemed to be a pivotal player in the comedy, becomes not only the first to die, but his death makes all those that follow inevitable. "Inevitability" is the force which governs the world of tragedy. From the time of Mercutio's death the characters seem to have no control over the events as they speed by. A sense of doom is dominant; events occur before they can be stopped; perceptions are marred; errors in judgment are rampant; everyone is inflexible; everything is absolute, inevitable. The stage has been set for the tragedy.