Arrow Photos from "The Promise"
On Arrow Season 2 Episode 15 - titled "The Promise" - Oliver, Slade and Sara prepare to take control of the freighter from Ivo.
Unknown to Slade, Sara talks Oliver into killing Ivo to ensure Slade never learns the truth about what happened to Shado.
In the present day, Oliver is shocked to learn that Slade is alive and well, living in Starling City and in his living room in the Queen mansion!
You know Oliver, somebody once told me that secrets have weight. The more you keep, the harder it is to keep moving.Diggle
Ra's al Ghul: You tasted death and you wanted more, but the truth is everyone and everything must come to an end. Even for one such as me.
Oliver: Kill me, but spare John Diggle's life. Let him go. I will beg for it.
Ra's al Ghul: You have shown tremendous strength, fortitude, power. No, Mr. Queen. I don't want to kill you. I want you to take my place. I want you to become the next Ra's al Ghul.