EXCLUSIVE: 'Arrow' Boss Dishes on That Flashpoint Shocker and Season 5's Different Breed of Big Bad

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Killing is back on the table for Oliver Queen (Stephen Amell) in season five of Arrow, and for executive producer Marc Guggenheim, it’s not so much a regression to his early days as The Hood, but a new journey entirely for the Green Arrow.

“Once we decided that Oliver was capable of killing Damien Darhk at the end of season four, that begged the question of, 'Where does Oliver stand with respect to killing in season five?'” Guggenheim explained to ET’s Leanne Aguilera. “Unlike season one where Oliver was basically killing everyone that he would encounter, and unlike seasons two through four where Oliver was very much like, 'I'm absolutely not killing,' we thought, 'Oh, there's an opportunity here for there to be a hybrid.'”

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“Oliver is trying to have a balance -- emphasis on the word try,” he added. “It's a bit of a struggle… I think Oliver made a good case to Thea [in the season five premiere] as to why it was necessary, and I think Thea made a good case back as to why she felt that it was a digression.”

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Fans also met the season’s big bad, Prometheus, in the final moments of last week’s premiere, and while the ominous masked archer seems to be taking a page from Green Arrow’s book, Guggenheim says the villain is like nothing we’ve seen before.

“I think every year we sort of try to come up with a different kind of villain for Oliver to face, and every year I think we sort of succeed,” he explained. “Like them or not, the big bads of each year have been very different from all the other big bads, so certainly we knew going into season five that we weren’t going to do another magical villain because we just had Damien Dahrk.”

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“We were thinking about, 'Well, what can Arrow do as a show that Flash, Supergirl and Legends can't do?'” he added. “Arrow has been on the longest, which means that Oliver Queen and the character of the Green Arrow has the longest history, so what if we were to create a villain who was pulled from that history? In other words, tell a story about a villain that we could only tell on the fifth season of the show.”

Some Arrow fans are hoping that the villain "pulled" from Oliver’s history could be none other than his old best friend, Tommy Merlyn (Colin Donnell). While Tommy died in the show’s season one finale, his malevolent father, Malcolm Merlyn (John Barrowman), has seemingly had nine lives in the DCTV ‘verse, wreaking havoc across several storylines.

“I've absolutely heard that theory,” Guggenheim admitted. “It's always very tricky because if Tommy were under the hood, then I think that would be pretty cool, but at the same Colin Donnell is a series regular on another show [NBC’s Chicago Med]. I'll leave it there. I'm going to stand pat on that answer.”

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As the show ramps up towards The CW’s epic, four-show crossover with fellow DC Comics headliners The Flash, Supergirl, and Legends of Tomorrow, fans will start to see some of the events of the other storylines -- namely, The Flash’s world-shifting Flashpoint -- seep into their character’s lives. For example, on Tuesday’s episode of The Flash, it was revealed that Diggle (John Ramsey) and his wife, Lyla (Audrey Marie Anderson), are now parents to a son, instead of the daughter, Sara, that they welcomed back in season three.

“The ramifications of that will really get dealt with on Flash, appropriately, then on Arrow,” Guggenheim explained. “We sort of have our own story to tell on Arrow and it will be something that is obviously reflected on Arrow. A lot of the ramifications really play mainly on Flash.”

As for the rest of Team Arrow, Wednesday’s episode will show Oliver beginning to train his new team of recruits: Curtis Holt (Echo Kellum), Wild Dog (Rick Gonzalez) and Evelyn Sharp (Madison McLaughlin). But is he ready to fulfill Laurel’s (Katie Cassidy) dying wish: to help someone else assume the Black Canary mantle?

“It’s definitely possible. I never like to say you'll absolutely see something or you absolutely won't,” Guggenheim teased. “I will say that's not going to happen in the early going. If it were to happen, it would probably happen in the latter half of the season.”

airs Wednesdays at 8 p.m. ET/PT on The CW.

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