The original Suicide Squad faced off with monsters in the comics. Only later was the '59 team reinvented by John Ostrander in 1987 into the "Dirty Dozen"-style black ops outfit of villains we know today.
Through the years the Suicide Squad has recruited numerous villains to work for the government. Many characters have failed to make it home from some of the team's missions, ensuring the Suicide Squad lives up to its name.
While the team called Suicide Squad was introduced in the comic The Brave and the Bold #25 way back in 1959, Harley Quinn only became a member in 2011. In fact, she wasn't even a comic character originally, first appearing the 1990s "Batman: The Animated Series".
In the movie Harley Quinn -- real name Harleen Quinzel, a psychologist -- is played by Australian actress Margot Robbie. She swings a baseball bat instead of a comically oversized mallet, but has the same quirky and uninhibited attitude as her comic book character, not to mention the same troubled relationship with the murderous Joker.
Will Smith plays Floyd Lawton, better known as Deadshot. Aided by an electronic eyepiece, he never misses a shot. First appearing in Batman #59 in 1950 as a tuxedo-wearing vigilante, he's evolved into an assassin with a tragic family history. In the comic he often leads the Suicide Squad, and Smith is certainly the biggest name leading the cast.
Contrary to what one might think, the Joker has never been part of the Suicide Squad. However, the Joker, played by Jared Leto (pictured, left), will have an important role thanks to his history with squad member Harley Quinn.
The appearance of the Joker in the movie has two clear inspirations: the controversial graphic novel "The Killing Joke" (pictured right) by Alan Moore, Brian Bolland and John Higgins; and the tattooed Joker seen in Frank Miller's mercifully unfinished "All-Star Batman & Robin".
The man in charge of keeping the Suicide Squad in line is Rick Flag Jr. The original team was led during World War II by Flag's father before he took charge. Flag Jr. is an expert in military combat tactics and espionage. Joel Kinnaman plays Flag in the movie, recruiting the team of villains and leading them on the battlefield.
The mysterious Enchantress is played by model and actor Cara Delevingne. In the comic, Enchantress is a powerful witch, first appearing in Strange Adventures #187 in April 1966. In the film, June Moone is an ordinary woman who is possessed by an ancient evil force and transformed into the black-clad Enchantress.
Captain Boomerang is an Australian villain, dexterous with his native country's boomerang and sworn enemy of superhero the Flash. He has been a member of the Suicide Squad since its inception. In the film he's played by Jai Courtney from "Terminator Genisys", and, like Margot Robbie, is Australian himself.
The members of the Suicide Squad are supervillains, so you can imagine that the person who decides to gather them has to be just as cunning. That's the case with the calculating government operative Amanda Waller, who in the comic doesn't hesitate to threaten even Batman when he investigates the existence of the Suicide Squad. In the film Waller is played by Viola Davis.
In the comics, Killer Croc is one of Batman's enemies, first appearing in the caped crusader's comic in 1983. Held at Belle Reve prison, he is recruited to join the Suicide Squad in exchange for reducing his sentence. The film tones down Croc's rather literal appearance from the comic, burying actor Adewale Akinnuoye-Agbaje under layers of make-up to play a murderous cannibal with reptilian skin.
Katana is another character who first challenged Batman before joining the Suicide Squad. Her tragic story has deep roots in Japanese tradition. In the film Katana is played by newcomer Karen Fukuhara. Her sword is called Soultaker, which catches the souls of her victims.
Perhaps the villain whose appearance has changed most from comic book to film is Slipknot, played in the film by Native American actor Adam Beach. Originally dressed in a masked suit, Slipknot is a master of ropes, having developed some that are impossible to break.