Ra's al Ghul (Earth-4678)

"I have used the Lazarus Pit too many times. I've lived 600 years. My mind and body cannot take much more. Each time I enter the pit, I am frightened of what will come out!"

- Ra's al Ghul

Ra's al Ghul was the immortal leader of the League of Assassins, whose name meant "The Demon's Head". Ra's lived for many centuries due to Lazarus Pit, which contained a mystical and alchemical brew, Lazarus, that restored his youth. A brilliant master of strategy and organization, Ra's goal was to save the Earth from ecological and criminal devastation by destroying most of its population.

Ra's recognized Batman as both a worthy foe and a possible ally - except that Batman did not accept his dystopic worldview and the killing of criminals. In order to bring Batman to his side, Ra's even orchestrated a relationship between Batman and his daughter, Talia al Ghul.

Source

 * https://dc.fandom.com/wiki/Ra%27s_al_Ghul_(Arkhamverse)