Batman: The Animated Series1992

[Ra's reveals the identity of his captive]

Batman:
Duvall.

Robin:
It can't be! He'd be over a hundred years old!

Ra's Al Ghul:
He was sentenced to fifty years at hard labor. Of course no one expected him to survive that sentence. No one but me.

Batman:
The Lazarus Pit.

Ra's Al Ghul:
When he was a young man. Though even its powers cannot restore him now. When his sentence was completed, Arkady simply wandered away. The privations he had suffered had left his mind shattered. I had lost track of him until I found him in that rest home.

Batman:
You left Duvall to his fate a century ago. Why come back for him now?

Ra's Al Ghul:
Did you really imagine, Detective, that in my six-hundred years of life, that I had sired only one offspring? Even before the Phoenix debacle I realized that Arkady was too mentally unbalanced and cruel to wisely rule my empire.

Batman:
But you didn't forget him.

Ra's Al Ghul:
What father can ever forget his son? Come Detective, I've still a few good years left. We will cross swords some other time. But for now... let me take my boy home.