Many characters have died on Arrow, but few of those deaths have been as tragic as Tommy Merlyn’s. A main cast member in Season 1, Tommy died during that season’s finale. However, the writers of Arrow still have Tommy on the mind, and if you’re a fan of the character, you’re in for a treat during the third season. like a typical comic book property, Arrow isn't letting this dead guy rest in peace.
Actor Colin Donnell has actually reprised the role of Tommy twice since he was officially killed off. While talking about Tommy’s reappearance earlier this season, executive producer Marc Guggenheim was asked by E! News whether Tommy would show up again. Citing the love the Arrow cast and crew have for Donnell, Guggenheim confirmed that viewers will get to see Tommy again.
"We love Colin Donnell and we love having him on the show. I was on set for his scene at the end of Season one and the second we wrapped him, I said to him, "I'm so glad we do flashbacks on this show!" So yes, you have not seen the last of Tommy Merlyn."
However, this revelation also comes with a stipulation.
“Though I will say this, the next time you see Tommy Merlyn, you will see him again on the show but it won't be the way you're expecting.”
Although he was one of the show’s primary characters during Season 1, Tommy was accidentally killed after rescuing Laurel from the collapsed CNRI building. It was his death that caused Oliver to adopt his no-kill rule and led Laurel to turn to alcohol and drugs for dealing with her depression. Tommy has appeared beyond the grave twice since his passing. He appeared in the Season 2 episode “Three Ghosts” as a hallucination Oliver sees while fighting Cyrus Gold. He reappeared in Season 3’s “Sara” in Oliver’s flashbacks from Hong Kong. Tommy went there to try to find Oliver (who was still presumed dead), but Oliver was able to send his friend away anonymously before he got hurt. Here's Tommy in his prime.
Flashbacks, dreams and hallucinations have been the primary ways Arrow characters have appeared beyond the grave, but there is another possibility for Tommy’s return. The main villain this season is League of Assassins leader Ra’s al Ghul. In the comics, Ra’s has lived for hundreds of years by regularly bathing in the Lazarus Pits, chemical pools that can heal the sick and injured, keep a person young, and most importantly, resurrect the dead. In the New 52 continuity, this was how Batman’s former sidekick Jason Todd was revived. Despite being dead for two year, Tommy’s remains may be stolen and submerged into one of the Pits, except when he’s revived, he’ll somehow be different. Could this be our first zombie on Arrow?!?!
The problem with this idea is that the Arrow producers have said that the new episodes will remain grounded and not dive too deep into the fantastical elements of this universe--The Flash already has that covered. Bringing Tommy back to life using magic chemicals would majorly contradict that claim. Perhaps Guggenheim is just playing coy with the fans, and Tommy’s reappearance will happen through another flashback or dream sequence, which would still be great.