‘Orphan Black’
Mark (Ari Millen) was killed off in “Orphan Black” Season 5, episode 9. BBC America

“Orphan Black” Season 5 is all about goodbyes. Not only is the current season the final one for the series, but there are also some characters fans have had to say goodbye to before the finale.

Following Mrs. S’ (Maria Doyle Kennedy) shocking death in Season 5, episode 8, Ari Millen’s Mark was killed off in episode 9. Mark was the last of the Project Castor clones.

Read: Will another character die in the finale episode for “Orphan Black” Season 5?

Series creator Graeme Manson said that he felt it was the right time to say goodbye to the character. “It was a season of goodbyes, especially as we were wrapping up this year. We kept wrapping up cast and wrapping up characters, and those were emotional goodbyes. First of all, we said goodbye to Ari’s other character and then we said goodbye to Mark,” he told Entertainment Weekly.

“Orphan Black” executive producer John Fawcett admitted that it was difficult to say goodbye to Millen since they just bid farewell to Kennedy in the previous week. “Working with Ari has been a great experience. He’s really stepped up for us and has been fantastic through four seasons of ‘Orphan Black.’ It’s hard to say goodbye and we had to do that with Maria last week, and that was a really tough one for everyone. And then now again with Ari,” he said.

When asked who their favorite Castor clone was, Manson and Fawcett both said that they liked Mark the most. “He was our first and he was the character that Ari played, came in and knocked that role out of the park. That was not a role that was going to continue. That was a one-off part and its was off of that during that season that we decided that the story could twist around to reveal that Ari was the Castor clone,” Manson said.

Meanwhile, “Orphan Black” Season 5 only has one more episode left before the series officially wraps. According to Fawcett, it will be trying to have to say goodbye to the entire cast and the show after next Saturday’s installment. “It’s been an emotional experience, there’s no question,” he said.

“Orphan Black” Season 5, episode 10 will air on BBC America on Aug. 12 at 10 p.m. EDT.