Buffy Summers (played by Sarah Michelle Gellar) is the "Slayer", one in a long line of young women chosen by fate to battle evil forces. This mystical calling grants her powers that dramatically increase physical strength, endurance, agility, accelerated healing, intuition, and a limited degree of precognition. In contrast, Brendon's character, Xander is the only character without supernatural abilities, and provides comic relief and a grounded perspective. It is Xander who often provides the heart to the series, and in season six, becomes the hero in place of Buffy who defeats the "Big Bad". Buffy and Willow are the only characters who appear in all 144 episodes; Xander is missing in only one.