“Arrow” will finally reveal which character close to Oliver Queen (Stephen Amell) dies in Season 4, episode 18, titled “Eleven-Fifty-Nine.” The CW

After months of speculation, the biggest mystery of “Arrow” Season 4 is about to be solved. Since episode 1 of the hit CW series’ latest run, the show has teased the death of a yet-unknown character that will occur in Wednesday’s episode, “Eleven-Fifty-Nine.”

As previously reported, episode 18 of Season 4 will tear what’s left of Team Arrow apart when Malcolm Merlyn (John Barrowman) returns on behalf of H.I.V.E., along with his mysterious new benefactor, Andy Diggle (Eugene Byrd). With the episode’s synopsis promising that the previously forgotten villain, Damien Darhk (Neal McDonough), will be busted out of jail and possibly regain his magical powers, the deck is pretty heavily stacked against the already fragmented team on “Arrow.”

According to The Hollywood Reporter, the end result of this amalgam of villainy will be the death of a main character. Although the producers weren’t ready to reveal which cast member is doomed, they did say that episode 18 will be the one where someone dies.

“It’s going to be huge and significant,” executive producer Wendy Mericle told the outlet. “There's no question that it's going to be shocking. It was a shocking thing for us to process and to write the aftermath. We really wanted to make sure that we did it in a way that was very honorable and gave us space to honor all the characters' various reactions to it. The episodes we've written in the aftermath are devastating. They're meant to be. We wanted to explore that and have everybody feel the impact of this loss."

Sadly, every character on “Arrow” is potentially on the chopping block with the exception of Oliver (Stephen Amell) and Felicity (Emily Bett Rickards). In the teaser scene in question, posted below, Oliver is mourning over the grave of a friend when Barry Allen (Grant Gustin) from “The Flash” speeds up to the grave site and apologizes for being late. Oliver tells him that this could have been prevented if he’d had the nerve to kill the man responsible in the first place. With that, he joins Felicity in a limo and she encourages him to stop the mystery man at any cost. Right now, the most obvious guess for the person responsible for the murder is either Darhk or Merlyn, but with the constant twists and turns that make “Arrow” such an exciting show to watch, it’s really anyone’s guess.

Who do you think will be the one killed in Season 4, episode 18 of “Arrow”? Comment below or tweet your theories to @TylerMcCarthy.