In Legacy, the third volume of The Guardian Trilogy, Xander and Elizabeth begin their family and continue to travel the globe with SoulFire ministries, attempting to foil the schemes of Lucifer and his son, Gregory. Gregory seeks to increase his power and prestige in his quest for domination of the United States, the world, and ultimately, the universes. Light and dark forces fight on both the physical and spiritual planes, heading inevitably toward the final, epic battle.