Arrow Finale Scoop: Can Oliver Take Down Slade Wilson?

After vowing not to kill in his quest to be a hero, Oliver Queen (Stephen Amell) will face quite the conundrum in Arrow's season finale (Wednesday, 8/7c, The CW) as his season-long cat and mouse game with Slade Wilson (Manu Bennett) finally comes to a head.

"Our pitch for the season was that we wanted Oliver to go from being a vigilante who kills to being a hero who does not," executive producer Marc Guggenheim tells TVGuide.com. "With that dichotomy set up, we said we'd give every reason in the world to kill Slade Wilson and deal with the ramifications of that moral dilemma in the finale. The promos say kill or be killed and that's a good way of summarizing what Oliver is facing in the finale."

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And boy, has Slade really given Oliver a reason to kill him. Once an ally on the island, Slade turned dastardly evil after being injected with Mirakuru. Vowing revenge on Oliver after Slade learned that he inadvertently caused the death of Shado (Celina Jade), the villain known as Deathstroke has systematically taken Oliver's life apart, from enlisting Isabel Rochev (Summer Glau) to steal Queen Consolidated to killing his mother Moira (Susanna Thompson).

Though it feels like Slade is an unstoppable force, Oliver won't have to face him alone. In the finale, titled "Unthinkable," Oliver's ex-flame Sara (Caity Lotz) gets backup in the form of Nyssa (Katrina Law) and the League of Assassins, which makes for a pretty epic team that would make any comic book fan geek out. "It's by far the coolest scene we've ever shot on the show," Amell says of the goose bump-inducing lineup. Adds Guggenheim: "I love the visual of the Arrow standing alongside several dark archers in the Season 2 finale when Season 1's finale was Oliver versus the Dark Archer."

But the return of Nyssa isn't universally lauded, especially by Detective Lance (Paul Blackthorne). Setting the love triangle aside — Oliver's pretty busy trying to save Starling City, after all — Oliver will bury the hatchet with Sara's ex for the time being. "He needs Nyssa," Amell says. "He needs all the help that he can get. What Sara has done to convince Nyssa to help her is something that Oliver can't make an impact on."

But that's not to say Oliver doesn't recognize the fine line he's walking by turning to Nyssa for help. "Obviously there's a huge conflict of interest leaning on the League of Assassins, which Oliver makes clear to Sara in the finale," Guggenheim says. 

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As for those other important women in Oliver's life, both Laurel (Katie Cassidy) and Felicity (Emily Bett Rickards) will find themselves in grave danger. "Slade was very clear that one more person needs to die before this can end and he has vowed to kill the woman that Oliver loves," Guggenheim cryptically teases. When asked point blank if the grim reaper would visit Starling, the Arrow boss adds, "There is one character who we will not be seeing at the start of Season 3." 

But Slade isn't the only adversary Oliver will need to worry about in the finale. Amanda Waller (Cynthia Addai-Robinson) has set her sights on destroying Starling City to prevent any of Slade's Mirakuru army from escaping. On this front, Oliver will rely on Diggle (David Ramsey), who will cross paths with Suicide Squad member Deadshot (Michael Rowe) as he and Lyla (Audrey Marie Anderson) try to stop Waller. "It's always fun to see Diggle interact with Lyla and Deadshot, so we took the finale as an opportunity to get a little taste of that again," Guggenheim says, adding that we'll learn more about Oliver and Waller's connection. Also, "There's a fairly big development for Diggle in the finale that will set up his story for next year," he adds.

In all the chaos, don't expect Oliver to cross paths with his sister Thea (Willa Holland), last seen apparently shooting her father Malcolm (John Barrowman). But Thea will turn to Roy (Colton Haynes) — who will come one step closer to becoming a hero by donning a mask in the finale — for help. Guggenheim also teases bigger plans for Thea that have been in motion since they first pitched the second season to the network. "It's something that we spent the entire season building up to," he says. "Whether you know it or not, this is the completion of Thea's season-long journey."

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Of course, the season would not truly be complete without an ending both in Starling City and in the past. "We do something in the finale that we've never done on the show," Amell says. "Typically on the show, we have set flashback pieces, but our entire fourth and fifth act of the finale seamlessly intercut between the past and the present, [featuring] two moments between Slade and Oliver: the formative moment and the culmination of our battle in the present. It's really something."

"You've heard so much about what happened on the island with Slade and Oliver over the course of Season 2," Guggenheim says. "Oliver has talked about having the chance to cure him, but he chose to kill him instead, and has said that he drove an arrow through his eye. We've spent the last 22 episodes talking about the events of the finale in the flashbacks. All of this stuff you've been hearing about is going to come to a head."

Just how epic will their long-awaited showdown be in the past, where Oliver has boarded the freighter the Amazo in a bid to stop Slade? "We took our Amazo set and our amazing special effects department waterproofed the entire thing and flooded it with gallons upon gallons of water and we removed one section of the cells so we could get a techno-crane in there," Guggenheim says. "It is the scene of what I will say is one of the most epic fights that we've had on the show."

Ultimately, though, it will fall on Oliver in the present to take Slade down, possibly costing him his morals and beliefs in the process — or will it? "Can he do what he needs to do without killing people?" Amell ponders. "He needs to go to lengths in the finale that he's never gone to before; unthinkable lengths, pun intended, but that doesn't necessarily mean killing."

Arrow's season finale airs Wednesday at 8/7c on The CW.

(Full disclosure: TVGuide.com is owned by CBS, one of The CW's parent companies.)