Here's your guide to every Arrowverse member of the Suicide Squad who is also part of Task Force X in the DCEU. The first incarnation of the Suicide Squad appeared in the comics way back in 1959, but a recognizable version didn't make their debut until decades later. The basic idea is an inspired one; the jail cells of the DC Universe are packed with supervillains, and naturally, the government will be interested in striking deals to reduce their prison terms, just like the CIA employing convicted hackers and fraudsters in the real world. These are comics, of course, which meant the idea soon became rather extreme; members of Task Force X famously have bombs implanted in their brains, primed to detonate the moment they step out of line.
The Arrowverse started building up to introducing its own version of the Suicide Squad as early as Arrow season 2, when it introduced Amanda Waller, the shady director of ARGUS who founded the team in the comics. Soon the villains who survived encounters with Oliver Queen were winding up drafted into Task Force X, with John Diggle usually taking charge of their missions. Unfortunately, off-screen politics caused problems because Warner Bros. was wary of double-dipping characters; they tended to restrict the Arrowverse from using heroes, villains, and even secondary characters if they planned to bring them to the big screen as part of the DCEU. As a result, most members of the Arrowverse's Suicide Squad met an untimely end. Arrow season 7 introduced a new Suicide Squad in all but name but went out of their way to avoid angering the higher-ups by acknowledging it as such.
Still, that does naturally mean there's an interesting overlap between the Suicide Squad (briefly) seen in the Arrowverse and the one featured in David Ayer's Suicide Squad, as well as James Gunn's upcoming sequel/reboot The Suicide Squad. Here are all the Arrowverse team members who are making their way into the movies through Task Force X.
Amanda Waller
You can't have any incarnation of the Suicide Squad without Amanda Waller, the shady government agent responsible for founding Task Force X. The Arrowverse's version was played by Cynthia Addai-Robinson in Arrow seasons 2 through 4, and she was the corrupt director of ARGUS. Waller became a key ally for Team Arrow, but ultimately paid a fatal price for her ways when she was shot unceremoniously by the leader of a terrorist group called Shadowspire. In reality, Waller's death was mandated by Warner Bros. because they knew she was about to make her DCEU debut, where she was played by Viola Davis. As in the Arrowverse, Waller is a seriously dangerous government official who serves as director of ARGUS and the creator of Task Force X. Although both iterations are superb, Davis is remarkably comic-book-accurate; she visually resembles Waller, to such an extent the casting choice appears as inspired as Patrick Stewart's playing Charles Xavier in the X-Men films.
Boomerang
Nicknamed "Captain Boomerang" by Cisco Ramone, Digger Harkness appeared in Arrow as a former member of the Australian Secret Service who'd gone rogue. He served in Task Force X for a time, but escaped, and targeted Lyla Matthews for revenge. Although Captain Boomerang met with an untimely end (something he has in common with a lot of Task Force X members in the Arrowverse), future scenes in The Flash hinted he may well come back from the dead. The DCEU's Captain Boomerang is a bank robber who found himself on the wrong side of the Flash and was subsequently recruited into Task Force X in David Ayer's Suicide Squad. An Easter egg in Birds of Prey confirms Captain Boomerang subsequently escaped, but he'll be back in Task Force X for James Gunn's The Suicide Squad. In the DCEU, Captain Boomerang is played by Jai Courtney; the Arrowverse's version was played by Nick E. Tarabay.
Deadshot
The Arrowverse and the DCEU both have their own versions of Deadshot, and there are striking similarities between the two portrayals. Michael Rowe played Deadshot in the first three seasons of Arrow, and he was celebrated as the world's greatest marksman. Floyd Lawton was a family man, and he sent most of the money he earned from his assassinations to his daughter Zoe. He became an ARGUS agent and a member of the Arrowverse's Task Force X, before being apparently killed on a mission to Kasnia; Rowe thinks Deadshot is probably still alive and is willing to return, however unlikely that may be. The DCEU's Deadshot was played by Will Smith himself; he was just as much a family man and became one of the starring characters in David Ayer's Suicide Squad. As popular as he may have been, Smith won't be appearing in the sequel. Presumably, in the Arrowverse, he's either earned his parole or been killed.
Harley Quinn
In 2014, Arrow season 2 began teasing the introduction of Harley Quinn, revealing she was a prisoner in pigtails held by ARGUS. Unfortunately, DC Films had big plans for Harley Quinn and feared overexposing the character, so the Harley Quinn teases never went anywhere. While this is a shame, the DCEU has at least made the most of Harley Quinn, with Margot Robbie bringing her to life in Suicide Squad, Birds of Prey, and the upcoming The Suicide Squad. Robbie has come to define the live-action role in a remarkable way, proving she really is the best woman for the job of the therapist-turned-psycho-turned-vigilante.
Javelin
Finally, there's Javelin, a minor DC villain who appeared in Arrow season 7 and is set to make his DCEU debut in James Gunn's The Suicide Squad. Played by Yanik Ethier, Arrow's Javelin was a French criminal arrested by ARGUS with the help of Curtis Holt - which means he could easily wind up in a future iteration of Task Force X. Even comic book readers wouldn't be able to recognize him without his being credited as Javelin in the credits. In contrast, James Gunn's Javelin is played by Flula Borg and will be a lot more comic-book-accurate.