John Barrowman was asked about Malcolm Merlyn's comments in the last episode of Arrow suggesting Sara (Caity Lotz) has to kill Thea (Willa Holland) and in his response he revealed that Season 4 baddie Damien Darhk (Neal McDonough) has taken a dip in the regenerative water of the Lazarus Pit as well.
"He’s not afraid of her because, in his mind, he killed her once, he can kill her again,” Barrowman told Entertainment Weekly. "But he doesn’t know what she’s come out of the pit with. Everybody comes out of the pit different. People come out with a bit of every soul that has been put in the pit before. Some parts of those souls take over. Thea’s got a bloodlust. Damien Darhk’s got something else. What will Sara come out with?"
It was previously revealed by Ra's al Ghul (Matthew Nable) that when Damien left The League of Assassins he took with him waters from the Lazarus Pit. That has allowed him to live longer than the average person -- presumably a few hundred years. However, there was no mention of him having died before and being resurrected.
Arrow airs on Wednesday nights at 8 p.m. ET/PT on The CW.