Ra's al Ghul (title)

Ra's al Ghul is a title held by those who are the leader of the League of Assassins. To date there have been at least two.

Overview
It is unknown of this applies to all Ra's al Ghul successors, but Oliver was chosen to be the next Ra's al Ghul because he survived a battle against the current Ra's al Ghul. Whoever holds the title of Ra's al Ghul leads the League of Assassins and has access to supernatural waters which can heal wounds and grant the user the ability to live for much longer than the normal human life span. The water's effect however, are not permanent and lose their effect on the user after an unknown solid period of time, requiring the current Ra's al Ghul to find a successor before his time runs out.