LEGO Monster Fighters is a theme introduced in May 2012. To date, ten sets have been released. Seven of the sets contain at least one Moon Stone, and in the background story, the monsters attempt to collect them to unleash doom on the Earth by eclipsing the Sun forever, allowing the land of monsters into the minifigure's realm. The stones are based on the monster contained in its respective set. A band of Monster Fighters, led by Doctor Rodney Rathebone, tries to find the stones before the evil Lord Vampyre uses them to eclipse the sun forever.