Ra's al Ghul is a DC Comics supervillain and is one of Batman's greatest enemies. His name is Arabic for "The Demon's Head," and references the name of the star Algol. Created by writer Dennis O'Neil and artist Neal Adams, he was introduced in Batman #232's "Daughter of the Demon" (June 1971). Given his high status as a supervillain, he has also come into conflict with Superman and other superheroes in the DC Universe.
Ra's al Ghul is an international terrorist and assassin whose ultimate goal is a world in perfect environmental balance. He believes that the best way to achieve this balance is to eliminate most of humanity. Ra's usually tries to assault the world's human populace with a biological weapon, such as a genetically-engineered virus. He is aided in this quest by the Lazarus Pits, reservoirs of rejuvenating chemicals that restore the dying to life; these pits have granted him a lifespan of several centuries.