Though Ra's al Ghul may be immortal, his corpse can be found in Batman: Arkham Asylum. The leader of the League of Assassins lies in a cooler in the morgue of the Arkham Manor inside a body bag, out of which his foot sticks out with an identification tag conveniently pinned on it. When the game first came out in 2009, there was almost no context for how Ra's al Ghul fit into the Arkham series's storyline, making his appearance as a corpse all the more confusing.
It may be surprising to hear that one of Batman Arkham's most important villains conquered death long before the city of Gotham even existed. In fact, it was at least over 600 years ago when Ra's discovered what he called «Lazarus Pits,» which are pools of alchemical liquids that can resurrect the dead and provide youth to the living. With these pits, Ra's gained extreme combat skills and intellect, but they also made him insane with ambition. Ra's sought to kill most of the world's population in order to prevent ecological catastrophes. He eventually made his way to Gotham because he saw the extreme levels of crime as hazardous but also because of the area's resources for Lazarus Pits. But when he saw the origins of Batman's career, Ra's considered him as a potential ally in his goals and even hoped that the caped crusader would one day replace him, not accepting that to do so would go against everything the Batman believes.
Related: Batman: Arkham Knight — Why Letting Ra's Die Was The Right Choice
As a result of Ra's's attempts to get Batman join the League of Assassins through violence and manipulation, the two fought so harshly that Batman accidentally took Ra's's life. It is for this reason that the League of Assassins' leader's corpse can be found in Arkham
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