Throughout Season 4 of “Arrow” on the CW, fans have been teased with the death of an unknown character by its end. Now, in new promotions of episode 18, titled “Eleven-Fifty-Nine,” it appears viewers may finally have to brace themselves for the big moment when a key player may bid us farewell for good.

After the return of the villain Brie Larvan, played by “The Walking Dead” star Emily Kinney, things looked good for Team Arrow in episode 17, despite the fact their superhacker, Felicity Smoak (Emily Bett Rickards), decided to quit the group. However, it was revealed that Malcolm Merlyn (John Barrowman) is continuing down his path of villainy, having teamed up with HIVE to replace Damien Darhk (Neal McDonough) after the team put him in jail. The episode ended with Merlyn revealing that he’s working with Andy Diggle (Eugene Byrd), the believed-to-be-rehabilitated brother of John Diggle (David Ramsey).

Merlyn visited Darhk in jail and revealed that neither he nor HIVE had a plan to break him out. However, according to the official plot synopsis of episode 18, the villain will go back on that promise and draw the attention of Oliver Queen (Stephen Amell) in the process. When the hero discovers the plan to bust Darhk out of jail, he apparently also figures out that Andy is now pulling strings of his own.

In a teaser video of next week’s episode, the Green Arrow has cornered Andy, but the former soldier pleads with his brother for help. Diggle seems willing to side with his blood at the expense of the masked vigilante, who also happens to be his best friend, by threatening to shoot him.

Additionally, Merlyn can be seen in a brawl with his daughter, Thea (Willa Holland), but it’s unclear why she’s finally going after her villainous dad. Perhaps there’s still some unfinished business left over from the time he chose the League of Assassins over her life. It’s possible the bout between father and daughter doesn’t go well for Speedy as the teaser cuts to a hospital room where an unknown character is flat-lining. Is Thea going to die at Merlyn’s hand, prompting Oliver to vow revenge and break his code to never kill anyone?

“Arrow” Season 4, episode 18 will air on the CW Tuesday, April 6, at 8 p.m. EDT. Fans will just have to wait until then to see whether this is the moment when Oliver and Felicity lose someone close to them.