Fans can expect more action as The CW's "Arrow" heads toward the finale of its fifth season. A finale battle is underway, which will bring back characters from past seasons, and it is going to be a big one.

The synopsis for the finale episode reveals the return of iconic characters who will participate in the epic battle between Oliver Queen/Green Arrow (Stephen Amell) and Adrian Chase/Prometheus (Josh Segarra) on the island of Lian Yu, where the story of the Green Arrow all began. Fans will see Earth-2 Laurel Lance/Black Siren (Katie Cassidy), Evelyn Sharp (Madison McLaughlin), and Talia al Ghul (Lexa Doig) on Adrian's side of the war, while Slade Wilson/Deathstroke (Manu Bennett), Nyssa al Ghul (Katrina Law), Malcolm Merlyn (John Barrowman), and Digger Harkness/Captain Boomerang (Nick E. Tarabay) will be on Oliver's.

Deathstroke has not been seen on the show for several seasons as he was imprisoned in Lian Yu, but Oliver will recruit him, a former friend turned villain, in order to defeat this season's big bad.

Captain Boomerang, a former member of the Suicide Squad formed by A.R.G.U.S., has been spending time in the same prison. He previously tried to kill Lyla Michaels (Audrey Marie Anderson) out of grudge and attempted to bomb Star City back in season 3. Many of the show's fans have been waiting for the character to return. According to Movie Pilot, his comeback may have been delayed because of Captain Boomerang's big screen debut in "Suicide Squad" last year.

With this all-star lineup for the season's epic finale battle, it is impossible to have zero casualties. It has been speculated that one of the casualties will be Barrowman's character since it was reported that he will no longer be returning to the "Arrowverse" next season. Also, executive producer Wendy Mericle revealed in an interview with Comic Book Resources that Malcolm will be playing a huge role in the finale, which hints that it might be his last appearance.

"He's going to be a huge factor leading up to the finale," she told the publication. "This season is all about legacy, and when Malcolm comes into the story, it's really rooted as much by necessity from Oliver's point of view as it is about what Malcolm means to him and what Malcolm means to Thea."

"Arrow" season 5 airs Wednesdays at 8 p.m. EDT on The CW.